Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
System and Method for Storing
Program Code and Data Within an Application Hosting Center
RELATED APPLICATION
[0001] This application is a continuation-in-part (CIP) application of
Serial No. 10/315, 460 filed December 10, 2002 entitled, "APPARATUS AND
METHOD FOR WIRELESS VIDEO GAMING", which is assigned to the assignee of the
present CIP application.
TECHNICAL FIELD
[0002] The present disclosure relates generally to the field of data
processing systems that improve a users' ability to manipulate and access
audio
and video media.
BACKGROUND
[0003] Recorded audio and motion picture media has been an aspect of
society since the days of Thomas Edison. At the start of the 20th century
there was
wide distribution of recorded audio media (cylinders and records) and motion
picture media (nickelodeons and movies), but both technologies were still in
their
infancy. In the late 1920s motion pictures were combined with audio on a mass-
market basis, followed by color motion pictures with audio. Radio broadcasting
gradually evolved into a largely advertising-supported form of broadcast mass-
market audio media. When a television (TV) broadcast standard was established
in the mid-1940s, television joined radio as a form of broadcast mass-market
media bringing previously recorded or live motion pictures into the home.
[0004] By the middle of the 20th century, a large percentage of US homes
had phonograph record players for playing recorded audio media, a radio to
receive live broadcast audio, and a television set to play live broadcast
audio /
video (A/V) media. Very often these 3 "media players" (record player, radio
and
TV) were combined into one cabinet sharing common speakers that became the
1
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
"media center" for the home. Although the media choices were limited to the
consumer, the media "ecosystem" was quite stable. Most consumers knew how to
use the "media players" and were able to enjoy the full extent of their
capabilities.
At the same time, the publishers of the media (largely the motion picture and
televisions studios, and the music companies) were able to distribute their
media
both to theaters and to the home without suffering from widespread piracy or
"second sales", i.e., the resale of used media. Typically publishers do not
derive
revenue from second sales, and as such, it reduces revenue that publishers
might
otherwise derive from the buyer of used media for new sales. Although there
certainly were used records sold during the middle of the 20th century, such
sales
did not have a large impact on record publishers because, unlike a motion
picture
or video program -- which is typically watched once or only a few times by an
adult -- a music track may be listened to hundreds or even thousands of times.
So,
music media is far less "perishable" (i.e., it has lasting value to an adult
consumer) than motion picture/video media. Once a record was purchased, if the
consumer liked the music, the consumer was likely to keep it a long time.
[0005] From the middle of the 20th century through the present day, the
media ecosystem has undergone a series of radical changes, both to the benefit
and the detriment of consumers and publishers. With the widespread
introduction
of audio recorders, especially cassette tapes with high-quality stereo sound,
there
certainly was a higher degree of consumer convenience. But it also marked the
beginning of what is now a widespread practice with consumer media: piracy.
Certainly, many consumers used the cassette tapes for taping their own records
purely for convenience, but increasingly consumers (e.g., students in a
dormitory
with ready access to each others' record collections) would make pirated
copies.
Also, consumers would tape music played over the radio rather than buying a
record or tape from the publisher.
[0006] The advent of the consumer VCR led to even more consumer
convenience, since now a VCR could be set to record a TV show which could be
2
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
watched at a later time, and it also led to the creation of the video rental
business,
where movies as well as TV programming could be accessed on an "on demand"
basis. The rapid development of mass-market home media devices since the mid-
1980s has led to an unprecedented level of choice and convenience for the
consumer, and also has led to a rapid expansion of the media publishing
market.
[0007] Today, consumers are faced with a plethora of media choices as
well as a plethora of media devices, many of which are tied to particular
forms of
media or particular publishers. An avid consumer of media may have a stack of
devices connected to TVs and computers in various rooms of the house,
resulting
in a "rat's nest" of cables to one or more TV sets and/or personal computers
(PCs) as well as a group of remote controls. (In the context of the present
application, the term "personal computer" or "PC" refers to any sort of
computer
suitable for us in the home or office, including a desktop, a Macintosh or
other
non-Windows computers, Windows-compatible devices, Unix variations, laptops,
etc.) These devices may include a video game console, VCR, DVD player, audio
surround-sound processor/amplifier, satellite set-top box, cable TV set-top
box,
etc. And, for an avid consumer, there may be multiple similar-function devices
because of compatibility issues. For example, a consumer may own both a HD-
DVD and a Blu-ray DVD player, or both a Microsoft Xbox and a Sony
Playstation video game system. Indeed, because of incompatibility of some
games across versions of game consoles, the consumer may own both an XBox
and a later version, such as an Xbox 360 . Frequently, consumers are befuddled
as to which video input and which remote to use. Even after a disc is placed
into
the correct player (e.g., DVD, HD-DVD, Blu-ray, Xbox or Playstation), the
video
and audio input is selected for that the device, and the correct remote
control is
found, the consumer is still faced with technical challenges. For example, in
the
case of a wide-screen DVD, the user may need to first determine and then set
the
correct aspect ratio on his TV or monitor screen (e.g., 4:3, Full, Zoom, Wide
Zoom, Cinema Wide, etc.). Similarly, the user may need to first determine and
3
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
then set the correct audio surround sound system format (e.g., AC-3, Dolby
Digital, DTS, etc.). Often times, the consumer is unaware that they may not be
enjoying the media content to the full capability of their television or audio
system (e.g., watching a movie squashed at the wrong aspect ratio, or
listening to
audio in stereo rather than in surround sound).
[0008] Increasingly, Internet-based media devices have been added to the
stack of devices. Audio devices like the Sonos Digital Music system stream
audio directly from the Internet. Likewise, devices like the SlingboxTM
entertainment player record video and stream it through a home network or out
through the Internet where it can be watched remotely on a PC. And Internet
Protocol Television (IPTV) services offer cable TV-like services through
Digital
Subscriber Line (DSL) or other home Internet connections. There have also been
recent efforts to integrate multiple media functions into a single device,
such as
the Moxi Media Center and PCs running Windows XP Media Center Edition.
While each of these devices offers an element of convenience for the functions
that it performs, each lacks ubiquitous and simple access to most media.
Further,
such devices frequently cost hundreds of dollars to manufacture, often because
of
the need for expensive processing and/or local storage. Additionally, these
modern consumer electronic devices typically consume a great deal of power,
even while idle, which means they are expensive over time and wasteful of
energy resources. For example, a device may continue to operate if the
consumer
neglects to turn it off or switches to a different video input. And, because
none of
the devices is a complete solution, it must be integrated with the other stack
of
devices in the home, which still leaves the user with a rat's nest of wires
and a sea
of remote controls.
[0009] Furthermore, when many newer Internet-based devices do work
properly, they typically offer media in a more generic form than it might
otherwise be available. For example, devices that stream video through the
Internet often stream just the video material, not the interactive "extras"
that often
4
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
accompany DVDs, like the "making of videos, games, or director's commentary.
This is due to the fact that frequently the interactive material is produced
in a
particular format intended for a particular device that handles interactivity
locally.
For example, each of DVD, HD-DVDs and Blu-ray discs have their own
particular interactive format. Any home media device or local computer that
might be developed to support all of the popular formats would require a level
of
sophistication and flexibility that would likely make it prohibitively
expensive
and complex for the consumer to operate.
[0010] Adding to the problem, if a new format were introduced later in
the future the local device may not have the hardware capability to support
the
new format, which would mean that the consumer would have to purchase an
upgraded local media device. For example, if higher-resolution video or
stereoscopic video (e.g., one video stream for each eye) were introduced at a
later
date, the local device may not have the computational capability to decode the
video, or it may not have the hardware to output the video in the new format
(e.g.,
assuming stereoscopy is achieved through 120fps video synchronized with
shuttered glasses, with 60fps delivered to each eye, if the consumer's video
hardware can only support 60fps video, this option would be unavailable absent
an upgraded hardware purchase).
[0011] The issue of media device obsolescence and complexity is a
serious problem when it comes to sophisticated interactive media, especially
video games.
[0012] Modern video game applications are largely divided into four
major non-portable hardware platforms: Sony PlayStation 1, 2 and 3 (PS1, PS2,
and PS3); Microsoft Xbox and Xbox 360 ; and Nintendo Gamecube and
WiiTM; and PC-based games. Each of these platforms is different than the
others
so that games written to run on one platform usually do not run on another
platform. There may also be compatibility problems from one generation of
device to the next. Even though the majority of software game developers
create
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
software games that are designed independent of a particular platform, in
order to
run a particular game on a specific platform a proprietary layer of software
(frequently called a "game development engine") is needed to adapt the game
for
use on a specific platform. Each platform is sold to the consumer as a
"console"
(i.e., a standalone box attached to a TV or monitor/speakers) or it is a PC
itself.
Typically, the video games are sold on optical media such as a Blu-ray DVD,
DVD-ROM or CD-ROM, which contains the video game embodied as a
sophisticated real-time software application. As home broadband speeds have
increased, video games are becoming increasingly available for download.
[0013] The specificity requirements to achieve platform-compatibility
with video game software is extremely exacting due to the real-time nature and
high computational requirements of advanced video games. For example, one
might expect full game compatibility from one generation to the next of video
games (e.g., from XBox to XBox 360, or from Playstation 2 ("PS2") to
Playstation 3 ("PS3"), just as there is general compatibility of productivity
applications (e.g., Microsoft Word) from one PC to another with a faster
processing unit or core. However, this is not the case with video games.
Because
the video game manufacturers typically are seeking the highest possible
performance for a given price point when a video game generation is released,
dramatic architectural changes to the system are frequently made such that
many
games written for the prior generation system do not work on the later
generation
system. For example, XBox was based upon the x86-family of processors,
whereas XBox 360 was based upon a PowerPC-family.
[0014] Techniques can be utilized to emulate a prior architecture, but
given that video games are real-time applications, it is often unfeasible to
achieve
the exact same behavior in an emulation. This is a detriment to the consumer,
the
video game console manufacturer and the video game software publisher. For the
consumer, it means the necessity of keeping both an old and new generation of
video game consoles hooked up to the TV to be able to play all games. For the
6
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
console manufacturer it means cost associated with emulation and slower
adoption of new consoles. And for the publisher it means that multiple
versions
of new games may have to be released in order to reach all potential consumers
--
not only releasing a version for each brand of video game (e.g., XBox,
Playstation), but often a version for each version of a given brand (e.g., PS2
and
PS3). For example, a separate version of Electronic Arts' "Madden NFL 08" was
developed for XBox, XBox 360, PS2, PS3, Gamecube, Wii, and PC, among other
platforms.
[0015] Portable devices, such as cellular ("cell") phones and portable
media players also present challenges to game developers. Increasingly such
devices are connected to wireless data networks and are able to download video
games. But, there are a wide variety of cell phones and media devices in the
market, with a wide range of different display resolutions and computing
capabilities. Also, because such devices typically have power consumption,
cost
and weight constraints, they typically lack advanced graphics acceleration
hardware like a Graphics Processing Unit ("GPU"), such as devices made by
NVIDIA of Santa Clara, CA. Consequently, game software developers typically
develop a given game title simultaneously for many different types of portable
devices. A user may find that a given game title is not available for his
particular
cell phone or portable media player.
[0016] In the case of home game consoles, hardware platform
manufacturers typically charge a royalty to the software game developers for
the
ability to publish a game on their platform. Cell phone wireless carriers also
typically charge a royalty to the game publisher to download a game into the
cell
phone. In the case of PC games, there is no royalty paid to publish games, but
game developers typically face high costs due to the higher customer service
burden to support the wide range of PC configurations and installation issues
that
may arise. Also, PCs typically present less barriers to the piracy of game
software
since they are readily reprogrammable by a technically-knowledgeable user and
7
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
games can be more easily pirated and more easily distributed (e.g., through
the
Internet). Thus, for a software game developer, there are costs and
disadvantages
in publishing on game consoles, cell phones and PCs.
[0017] For game publishers of console and PC software, costs do not end
there. To distribute games through retail channels, publishers charge a
wholesale
price below the selling price for the retailer to have a profit margin. The
publisher
also typically has to pay the cost of manufacturing and distributing the
physical
media holding the game. The publisher is also frequently charged a "price
protection fee" by the retailer to cover possible contingencies such as where
the
game does not sell, or if the game's price is reduced, or if the retailer must
refund
part or all of the wholesale price and/or take the game back from a buyer.
Additionally, retailers also typically charge fees to publishers to help
market the
games in advertising flyers. Furthermore, retailers are increasingly buying
back
games from users who have finished playing them, and then sell them as used
games, typically sharing none of the used game revenue with the game
publisher.
Adding to the cost burden placed upon game publishers is the fact that games
are
often pirated and distributed through the Internet for users to download and
make
free copies.
[0018] As Internet broadband speeds have been increasing and broadband
connectivity has become more widespread in the US and worldwide, particularly
to the home and to Internet "cafes" where Internet-connected PCs are rented,
games are increasingly being distributed via downloads to PCs or consoles.
Also,
broadband connections are increasingly used for playing multiplayer and
massively multiplayer online games (both of which are referred to in the
present
disclosure by the acronym "MMOG"). These changes mitigate some of the costs
and issues associated with retail distribution. Downloading online games
addresses some of the disadvantages to game publishers in that distribution
costs
typically are less and there are little or no costs from unsold media. But
downloaded games are still subject to piracy, and because of their size (often
8
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
many gigabytes in size) they can take a very long time to download. In
addition,
multiple games can fill up small disk drives, such as those sold with portable
computers or with video game consoles. However, to the extent games or
MMOGs require an online connection for the game to be playable, the piracy
problem is mitigated since the user is usually required to have a valid user
account. Unlike linear media (e.g., video and music) which can be copied by a
camera shooting video of the display screen or a microphone recording audio
from the speakers, each video game experience is unique, and can not be copied
using simple video/audio recording. Thus, even in regions where copyright laws
are not strongly enforced and piracy is rampant, MMOGs can be shielded from
piracy and therefore a business can be supported. For example, Vivendi SA's
"World of Warcraft" MMOG has been successfully deployed without suffering
from piracy throughout the world. And many online or MMOG games, such as
Linden Lab's "Second Life" MMOG generate revenue for the games' operators
through economic models built into the games where assets can be bought, sold,
and even created using online tools. Thus, mechanisms in addition to
conventional game software purchases or subscriptions can be used to pay for
the
use of online games.
[0019] While piracy can be often mitigated due to the nature of online or
MMOGs, online game operator still face remaining challenges. Many games
require substantial local (i.e., in-home) processing resources for online or
MMOGs to work properly. If a user has a low performance local computer (e.g.,
one without a GPU, such as a low-end laptop), he may not be able to play the
game. Additionally, as game consoles age, they fall further behind the state-
of-
the-art and may not be able to handle more advanced games. Even assuming the
user's local PC is able to handle the computational requirements of a game,
there
are often installation complexities. There may be driver incompatibilities
(e.g., if
a new game is downloaded, it may install a new version of a graphics driver
that
renders a previously-installed game, reliant upon an old version of the
graphics
9
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
driver, inoperable). A console may run out of local disk space as more games
are
downloaded. Complex games typically receive downloaded patches over time
from the game developer as bugs are found and fixed, or if modifications are
made to the game (e.g., if the game developer finds that a level of the game
is too
hard or too easy to play). These patches require new downloads. But sometimes
not all users complete downloading of all the patches. Other times, the
downloaded patches introduce other compatibility or disk space consumption
issues.
[0020] Also, during game play, large data downloads may be required to
provide graphics or behavioral information to the local PC or console. For
example, if the user enters a room in a MMOG and encounters a scene or a
character made up of graphics data or with behaviors that are not available on
the
user's local machine, then that scene or character's data must be downloaded.
This may result in a substantial delay during game play if the Internet
connection
is not fast enough. And, if the encountered scene or character requires
storage
space or computational capability beyond that of the local PC or console, it
can
create a situation where the user can not proceed in the game, or must
continue
with reduced-quality graphics. Thus, online or MMOG games often limit their
storage and/or computational complexity requirements. Additionally, they often
limit the amount of data transfers during the game. Online or MMOG games may
also narrow the market of users that can play the games.
[0021] Furthermore, technically-knowledgeable users are increasingly
reverse-engineering local copies of games and modifying the games so that they
can cheat. The cheats maybe as simple as making a button press repeat faster
than
is humanly possible (e.g., so as to shoot a gun very rapidly). In games that
support in-game asset transactions the cheating can reach a level of
sophistication
that results in fraudulent transactions involving assets of actual economic
value.
When an online or MMOGs economic model is based on such asset transactions,
this can result in substantial detrimental consequences to the game operators.
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0022] The cost of developing a new game has grown as PCs and
consoles are able to produce increasingly sophisticated games (e.g., with more
realistic graphics, such as real-time ray-tracing, and more realistic
behaviors, such
as real-time physics simulation). In the early days of the video game
industry,
video game development was a very similar process to application software
development; that is, most of the development cost was in the development of
the
software, as opposed to the development of the graphical, audio, and
behavioral
elements or "assets", such as those that may be developed for a motion picture
with extensive special effects. Today, many sophisticated video game
development efforts more closely resemble special effects-rich motion picture
development than software development. For instance, many video games
provide simulations of 3-D worlds, and generate increasingly photorealistic
(i.e.,
computer graphics that seem as realistic as live action imagery shot
photographically) characters, props, and environments. One of the most
challenging aspects of photorealistic game development is creating a computer-
generated human face that is indistinguishable from a live action human face.
Facial capture technologies such ContourTM Reality Capture developed by Mova
of San Francisco, CA captures and tracks the precise geometry of a performer's
face at high resolution while it is in motion. This technology allows a 3D
face to
be rendered on a PC or game console that is virtually indistinguishable from a
captured live action face. Capturing and rendering a "photoreal" human face
precisely is useful in several respects. First, highly recognizable
celebrities or
athletes are often used in video games (often hired at a high cost), and
imperfections may be apparent to the user, making the viewing experience
distracting or unpleasant. Frequently, a high degree of detail is required to
achieve a high degree of photorealism -- requiring the rendering of a large
number of polygons and high-resolution textures, potentially with the polygons
and/or textures changing on a frame-by-frame basis as the face moves.
11
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0023] When high polygon-count scenes with detailed textures change
rapidly, the PC or game console supporting the game may not have sufficient
RAM to store enough polygon and texture data for the required number of
animation frames generated in the game segment. Further, the single optical
drive
or single disk drive typically available on a PC or game console is usually
much
slower than the RAM, and typically can not keep up with the maximum data rate
that the GPU can accept in rendering polygons and textures. Current games
typically load most of the polygons and textures into RAM, which means that a
given scene is largely limited in complexity and duration by the capacity of
the
RAM. In the case of facial animation, for example, this may limit a PC or a
game
console to either a low resolution face that is not photoreal, or to a
photoreal face
that can only be animated for a limited number of frames, before the game
pauses, and loads polygons and textures (and other data) for more frames.
[0024] Watching a progress bar move slowly across the screen as a PC or
console displays a message similar to "Loading..." is accepted as an inherent
drawback by today's users of complex video games. The delay while the next
scene loads from the disk ("disk" herein, unless otherwise qualified, refers
to non-
volatile optical or magnetic media, as well non-disk media such as
semiconductor
"Flash" memory) can take several seconds or even several minutes. This is a
waste of time and can be quite frustrating to a game player. As previously
discussed, much or all of the delay may be due to the load time for polygon,
textures or other data from a disk, but it also may be the case that part of
the load
time is spent while the processor and/or GPU in the PC or console prepares
data
for the scene. For example, a soccer video game may allow the players to
choose
among a large number of players, teams, stadiums and weather conditions. So,
depending on what particular combination is chosen, different polygons,
textures
and other data (collectively "objects") may be required for the scene (e.g.,
different teams have different colors and patterns on their uniforms). It may
be
possible to enumerate many or all of the various permutations and pre-compute
12
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
many or all of the objects in advance and store the objects on the disk used
to
store the game. But, if the number of permutations is large, the amount of
storage
required for all of the objects may be too large to fit on the disk (or too
impractical to download). Thus, existing PC and console systems are typically
constrained in both the complexity and play duration of given scenes and
suffer
from long load times for complex scenes.
[0025] Another significant limitation with prior art video game systems
and application software systems is that they are increasingly using large
databases, e.g., of 3D objects such as polygons and textures, that need to be
loaded into the PC or game console for processing. As discussed above, such
databases can take a long time to load when stored locally on a disk. Load
time,
however, is usually far more severe if the database is stored a remote
location and
is accessed through the Internet. In such a situation it may take minutes,
hours, or
even days to download a large database. Further, such databases are often
created
a great expense (e.g., a 3D model of a detailed tall-masted sailing ship for
use in a
game, movie, or historical documentary) and are intended for sale to the local
end-user. However, the database is at risk of being pirated once it has been
downloaded to the local user. In many cases, a user wants to download a
database
simply for the sake of evaluating it to see if it suits the user's needs
(e.g., if a 3D
costume for a game character has a satisfactory appearance or look when the
user
performs a particular move). A long load time can be a deterrent for the user
evaluating the 3D database before deciding to make a purchase.
[0026] Similar issues occur in MMOGs, particularly as games that allow
users to utilize increasingly customized characters. For a PC or game console
to
display a character it needs to have access to the database of 3D geometry
(polygons, textures, etc.) as well as behaviors (e.g., if the character has a
shield,
whether the shield is strong enough to deflect a spear or not) for that
character.
Typically, when a MMOG is first played by a user, a large number of databases
for characters are already available with the initial copy of the game, which
is
13
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
available locally on the game's optical disk or downloaded to a disk. But, as
the
game progresses, if the user encounters a character or object whose database
is
not available locally (e.g., if another user has created a customized
character),
before that character or object can be displayed, its database must be
downloaded.
This can result in a substantial delay of the game.
[0027] Given the sophistication and complexity of video games, another
challenge for video game developers and publishers with prior art video game
consoles, is that it frequently takes 2 to 3 years to develop a video game at
a cost
of tens of millions of dollars. Given that new video game console platforms
are
introduced at a rate of roughly once every five years, game developers need to
start development work on those games years in advance of the release of the
new
game console in order to have video games available concurrently when the new
platform is released. Several consoles from competing manufactures are
sometimes released around the same time (e.g., within a year or two of each
other), but what remains to be seen is the popularity of each console, e.g.,
which
console will produce the largest video game software sales. For example, in a
recent console cycle, the Microsoft XBox 360, the Sony Playstation 3, and the
Nintendo Wii were scheduled to be introduced around the same general
timeframe. But years before the introductions the game developers essentially
had
to "place their bets" on which console platforms would be more successful than
others, and devote their development resources accordingly. Motion picture
production companies also have to apportion their limited production resources
based on what they estimate to be the likely success of a movie well in
advance of
the release of the movie. Given the growing level of investment required for
video games, game production is increasingly becoming like motion picture
production, and game production companies routinely devote their production
resources based on their estimate of the future success of a particular video
game.
But, unlike they motion picture companies, this bet is not simply based on the
success of the production itself; rather, it is predicated on the success of
the game
14
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
console the game is intended to run on. Releasing the game on multiple
consoles
at once may mitigate the risk, but this additional effort increases cost, and
frequently delays the actual release of the game.
[0028] Application software and user environments on PCs are becoming
more computationally intensive, dynamic and interactive, not only to make them
more visually appealing to users, but also to make them more useful and
intuitive.
For example, both the new Windows Vista operating system and successive
versions of the Macintosh operating system incorporate visual animation
effects. Advanced graphics tools such as Maya from Autodesk, Inc., provide
very sophisticated 3D rendering and animation capability which push the limits
of
state-of-the-art CPUs and GPUs. However, the computational requirements of
these new tools create a number of practical issues for users and software
developers of such products.
[0029] Since the visual display of an operating system (OS) must work on
a wide range of classes of computers -- including prior-generation computers
no
longer sold, but still upgradeable with the new OS - the OS graphical
requirements are limited to a large degree by a least common denominator of
computers that the OS is targeted for, which typically includes computers that
do
not include a GPU. This severely limits the graphics capability of the OS.
Furthermore, battery-powered portably computers (e.g., laptops) limit the
visual
display capability since high computational activity in a CPU or GPU typically
results in higher power consumption and shorter battery life. Portable
computers
typically include software that automatically lowers processor activity to
reduce
power consumption when the processor is not utilized. In some computer models
the user may lower processor activity manually. For example, Sony's VGN-
SZ280P laptop contains a switch labeled "Stamina" on one side (for low
performance, more battery life) and "Speed" on the other (for high
performance,
less battery life). An OS running on a portable computer must be able to
function
usably even in the event the computer is running at a fraction of its peak
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
performance capability. Thus, OS graphics performance often remains far below
the state-of-the-art available computational capability.
[0030] High-end computationally-intense applications like Maya are
frequently sold with the expectation that they will be used on high-
performance
PCs. This typically establishes a much higher performance, and more expensive
and less portable, least common denominator requirement. As a consequence,
such applications have a much more limited target audience than a general
purpose OS (or general purpose productivity application, like Microsoft
Office)
and typically sell in much lower volume than general purpose OS software or
general purpose application software. The potential audience is further
limited
because often times it is difficult for a prospective user to try out such
computationally-intense applications in advance. For example, suppose a
student
wants to learn how to use Maya or a potential buyer already knowledgeable
about
such applications wants to try out Maya before making the investment in the
purchase (which may well involve also buying a high-end computer capable of
running Maya). While either the student or the potential buyer could download,
or get a physical media copy of, a demo version of Maya, if they lack a
computer
capable of running Maya to its full potential (e.g., handling a complex 3D
scene),
then they will be unable to make an fully-informed assessment of the product.
This substantially limits the audience for such high-end applications. It also
contributes to a high selling price since the development cost is usually
amortized
across a much smaller number of purchases than those of a general-purpose
application.
[00311 High-priced applications also create more incentive for individuals
and businesses to use pirated copies of the application software. As a result,
high-
end application software suffers from rampant piracy, despite significant
efforts
by publishers of such software to mitigate such piracy through various
techniques. Still, even when using pirated high-end applications, users cannot
obviate the need to invest in expensive state-of-the-art PCs to run the
pirated
16
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
copies. So, while they may obtain use of a software application for a fraction
of
its actual retail price, users of pirated software are still required to
purchase or
obtain an expensive PC in order to fully utilize the application.
[0032] The same is true for users of high-performance pirated video
games. Although pirates may get the games at fraction of their actual price,
they
are still required to purchase expensive computing hardware (e.g., a GPU-
enhanced PC, or a high-end video game console like the XBox 360) needed to
properly play the game. Given that video games are typically a pastime for
consumers, the additional cost for a high-end video game system can be
prohibitive. This situation is worse in countries (e.g., China) where the
average
annual income of workers currently is quite low relative to that of the United
States. As a result, a much smaller percentage of the population owns a high-
end
video game system or a high-end PC. In such countries, "Internet cafes", in
which
users pay a fee to use a computer connected to the Internet, are quite common.
Frequently, such Internet cafes have older model or low-end PCs without high
performance features, such as a GPU, which might otherwise enable players to
play computationally-intensive video games. This is a key factor in the
success of
games that run on low-end PCs, such as Vivendi's "World of Warcraft" which is
highly successful in China, and is commonly played in Internet cafes there. In
contrast, a computationally-intensive game, like "Second Life" is much less
likely to be playable on a PC installed in a Chinese Internet cafe. Such games
are
virtually inaccessible to users who only have access to low-performance PCs in
Internet cafes.
[0033] Barriers also exist for users who are considering purchasing a
video game and would first like to try out a demonstration version of the game
by
downloading the demo through the Internet to their home. A video game demo is
often a full-fledged version of the game with some features disabled, or with
limits placed on the amount of game play. This may involve a long process
(perhaps hours) of downloading gigabytes of data before the game can be
17
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
installed and executed on either a PC or a console. In the case of a PC, it
may also
involve figuring out what special drivers are needed (e.g., DirectX or OpenGL
drivers) for the game, downloading the correct version, installing them, and
then
determining whether the PC is capable of playing the game. This latter step
may
involve determining whether the PC has enough processing (CPU and GPU)
capability, sufficient RAM, and a compatible OS (e.g., some games run on
Windows XP, but not Vista). Thus, after a long process of attempting to run a
video game demo, the user may well find out that the video game demo can't be
possibly played, given the user's PC configuration. Worse, once the user has
downloaded new drivers in order to try the demo, these driver versions may be
incompatible with other games or applications the user uses regularly on the
PC,
thus the installation of a demo may render previously operable games or
applications inoperable. Not only are these barriers frustrating for the user,
but
they create barriers for video game software publishers and video game
developers to market their games.
[0034] Another problem that results in economic inefficiency has to do
with the fact that given PC or game console is usually designed to accommodate
a certain level of performance requirement for applications and/or games. For
example, some PCs have more or less RAM, slower or faster CPUs, and slower
or faster GPUs, if they have a GPUs at all. Some games or applications make
take
advantage of the full computing power of a given PC or console, while many
games or applications do not. If a user's choice of game or application falls
short
of the peak performance capabilities of the local PC or console, then the user
may
have wasted money on the PC or console for unutilized features. In the case of
a
console, the console manufacturer may have paid more than was necessary to
subsidize the console cost.
[0035] Another problem that exists in the marketing and enjoyment of
video games involves allowing a user to watch others playing games before the
user commits to the purchase of that game. Several prior art approaches exist
for
18
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
the recording of video games for replay at a later time. For example, U.S.
Patent
No. 5,558,339 teaches recording game state information, including game
controller actions, during "gameplay" in the video game client computer (owned
by the same or different user). This state information can be used at a later
time to
replay some or all of the game action on a video game client computer (e.g.,
PC
or console). A significant drawback to this approach is that for a user to
view the
recorded game, the user must possess a video game client computer capable of
playing the game and must have the video game application running on that
computer, such that the gameplay is identical when the recorded game state is
replayed. Beyond that, the video game application has to be written in such a
way
that there is no possible execution difference between the recorded game and
the
played back game.
[0036] For example, game graphics are generally computed on a frame-
by-frame basis. For many games, the game logic sometimes may take shorter or
longer than one frame time to compute the graphics displayed for the next
frame,
depending on whether the scene is particularly complex, or if there are other
delays that slow down execution (e.g., on a PC, another process may be running
that takes away CPU cycles from the game applications). In such a game, a
"threshold" frame that is computed in slightly less than one frame time (say a
few
CPU clock cycles less) can eventually occur. When that same scene is computed
again using the exact same game state information, it could easily take a few
CPU
clock cycles more than one frame time (e.g., if an internal CPU bus is
slightly out
of phase with the an external DRAM bus and it introduces a few CPU cycle times
of delay, even if there is no large delay from another process taking away
milliseconds of CPU time from game processing). Therefore, when the game is
played back the frame gets calculated in two frame times rather than a single
frame time. Some behaviors are based on how often the game calculates a new
frame (e.g., when the game samples the input from the game controllers). While
the game is played, this discrepancy in the time reference for different
behaviors
19
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
does not impact game play, but it can result in the played-back game producing
a
different result. For example, if a basketball's ballistics are calculated at
a steady
60 fps rate, but the game controller input is sampled based on rate of
computed
frames, the rate of computed frames may be 53 fps when the game was recorded,
but 52 fps when the game is replayed, which can make the difference between
whether the basketball is blocked from going into the basket or not, resulting
in a
different outcome. Thus, using game state to record video games requires very
careful game software design to ensure that the replay, using the same game
state
information, produces the exact same outcome.
[0037] Another prior art approach for recording video game is to simply
record the video output of a PC or video game system (e.g., to a VCR, DVD
recorder, or to a video capture board on a PC). The video then can be rewound
and replayed, or alternatively, the recorded video uploaded to the Internet,
typically after being compressed. A disadvantage to this approach is that when
a
3D game sequence is played back, the user is limited to viewing the sequence
from only the point of view from which the sequence was recorded. In other
words, the user cannot change the point of view of the scene.
[0038] Further, when compressed video of a recorded game sequence
played on a home PC or game console is made available to other users through
the Internet, even if the video is compressed in real-time, it may be
impossible to
upload the compressed video in real-time to the Internet. The reason why is
because many homes in the world that are connected to the Internet have highly
asymmetric broadband connections (e.g., DSL and cable modem typically have
far higher downstream bandwidth than upstream bandwidth). Compressed high
resolution video sequences often have higher bandwidths than the upstream
bandwidth capacity of the network, making them impossible to upload in real-
time. Thus, there would be a significant delay after the game sequence is
played
(perhaps minutes or even hours) before another user on the Internet would be
able
to view the game. Although this delay is tolerable in certain situations
(e.g., to
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
watch a game player's accomplishments that occurred at a prior time), it
eliminates the ability to watch a game live (e.g., a basketball tournament,
played
by champion players) or with "instant replay" capability as the game is played
live.
[0039] Another prior art approach allows a viewer with a television
receiver to watch video games live, but only under the control of the
television
production crew. Some television channels, in both the US and in other
countries
provide video game viewing channels, where the television viewing audience is
able to watch certain video game users (e.g., top-rated players playing in
tournaments) on video game channels. This is accomplished by having the video
output of the video game systems (PCs and/or consoles) fed into the video
distribution and processing equipment for the television channel. This is not
unlike when the television channel is broadcasting a live basketball game in
which several cameras provide live feeds from different angles around the
basketball court. The television channel then is able to make use of their
video/audio processing and effects equipment to manipulate the output from the
various video game systems. For example, the television channel can overlay
text
on top of the video from a video game that indicates the status of different
players
(just as they might overlay text during a live basketball game), and the
television
channel can overdub audio from a commentator who can discuss the action
occurring during the games. Additionally, the video game output can be
combined with cameras recording video of the actual players of the games
(e.g.,
showing their emotional response to the game).
[0040] One problem with this approach is that such live video feeds must
be available to the television channel's video distribution and processing
equipment in real-time in order for it to have the excitement of a live
broadcast.
As previously discussed, however, this is often impossible when the video game
system is running from the home, especially if part of the broadcast includes
live
video from a camera that is capturing real-world video of the game player.
21
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
Further, in a tournament situation, there is a concern that an in-home gamer
may
modify the game and cheat, as previously described. For these reasons, such
video game broadcasts on television channels are often arranged with players
and
video game systems aggregated at a common location (e.g., at a television
studio
or in an arena) where the television production equipment can accept video
feeds
from multiple video game systems and potentially live cameras.
[0041] Although such prior art video game television channels can
provide a very exciting presentation to the television viewing audience that
is an
experience akin to a live sporting event, e.g., with the video game players
presented as "athletes", both in terms of their actions in the video game
world,
and in terms of their actions in the real world, these video game systems are
often
limited to situations where players are in close physical proximity to one
another.
And, since television channels are broadcasted, each broadcasted channel can
only show one video stream, which is selected by the television channel's
production crew. Because of these limitations and the high cost of broadcast
time,
production equipment and production crews, such television channels typically
only show top-rated players playing in top tournaments.
[0042] Additionally, a given television channel broadcasting a full-screen
image of a video game to the entire television viewing audience shows only one
video game at a time. This severely limits a television viewer's choices. For
example, a television viewer may not be interested in the game(s) shown at a
given time. Another viewer may only be interested in watching the game play of
a particular player that is not featured by the television channel at a given
time. In
other cases, a viewer may only be interested in watching a how an expert
player
handles a particular level in a game. Still other viewers may wish to control
the
viewpoint that a video game is seen from, which is different from that chosen
by
the production team, etc. In short, a television viewer may have a myriad of
preferences in watching video games that are not accommodated by the
particular
broadcast of a television network, even if several different television
channels are
22
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
available. For all of the aforementioned reasons, prior art video game
television
channels have significant limitations in presenting video games to television
viewers.
[0043] Another drawback of prior art video games systems and
application software systems is that they are complex, and commonly suffer
from
errors, crashes and/or unintended and undesired behaviors (collectively,
"bugs").
Although games and applications typically go through a debugging and tuning
process (frequently called "Software Quality Assurance" or SQA) before
release,
almost invariably once the game or application is released to a wide audience
in
the field bugs crop up. Unfortunately, it is difficult for the software
developer to
identify and track down many of the bugs after release. It can be difficult
for
software developers to become aware of bugs. Even when they learn about a bug,
there may only be a limited amount of information available to them to
identify
what caused the bug. For example, a user may call up a game developer's
customer service line and leave a message stating that when playing the game,
the
screen started to flash, then changed to a solid blue color and the PC froze.
That
provides the SQA team with very little information useful in tracking down a
bug. Some games or applications that are connected online can sometimes
provide more information in certain cases. For example, a "watchdog" process
can sometimes be used to monitor the game or application for "crashes". The
watchdog process can gather statistics about the status of the game or
applications
process (e.g., the status of the stack, of the memory usage, how far the game
or
applications has progressed, etc.) when it crashes and then upload that
information to the SQA team via the Internet. But in a complex game or
application, such information can take a very long time to decipher in order
to
accurately determine what the user was doing at the time of the crash. Even
then,
it may be impossible to determine what sequence of events led to the crash.
[0044] Yet another problem associated with PCs and game consoles is
that they are subject to service issues which greatly inconvenience the
consumer.
23
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
Service issues also impact the manufacturer of the PC or game console since
they
typically are required to send a special box to safely ship the broken PC or
console, and then incur the cost of repair if the PC or console is in
warranty. The
game or application software publisher can also be impacted by the loss of
sales
(or online service use) by PCs and/or consoles being in a state of repair.
[0045] Figure 1 illustrates a prior art video gaming system such as a Sony
Playstation 3, Microsoft Xbox 360 , Nintendo WiiTM, Windows-based
personal computer or Apple Macintosh. Each of these systems includes a central
processing unit (CPU) for executing program code, typically a graphical
processing unit (GPU) for performing advanced graphical operations, and
multiple forms of input/output (1/0) for communicating with external devices
and
users. For simplicity, these components are shown combined together as a
single
unit 100. The prior art video gaming system of Figure 1 also is shown
including
an optical media drive 104 (e.g., a DVD-ROM drive); a hard drive 103 for
storing video game program code and data; a network connection 105 for playing
multi-player games, for downloading games, patches, demos or other media; a
random access memory (RAM) 101 for storing program code currently being
executed by the CPU/GPU 100; a game controller 106 for receiving input
commands from the user during gameplay; and a display device 102 (e.g., a
SDTV/HDTV or a computer monitor).
[0046] The prior art system shown in Figure 1 suffers from several
limitations. First, optical drives 104 and hard drives 103 tend to have much
slower access speeds as compared to that of RAM 101. When working directly
through RAM 101, the CPU/GPU 100 can, in practice, process far more polygons
per second than is possible when the program code and data is read directly
off of
hard drive 103 or optical drive 104 due to the fact that RAM 101 generally has
much higher bandwidth and does not suffer from the relatively long seek delays
of disc mechanisms. But only a limited amount of RAM is provided in these
prior art systems (e.g., 256-512Mbytes). Therefore, a "Loading..." sequence in
24
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
which RAM 101 is periodically filled up with the data for the next scene of
the
video game is often required.
[0047] Some systems attempt to overlap the loading of the program code
concurrently with the gameplay, but this can only be done when there is a
known
sequence of events (e.g., if a car is driving down a road, the geometry for
the
approaching buildings on the roadside can be loaded while the car is driving).
For complex and/or rapid scene changes, this type of overlapping usually does
not work. For example, in the case where the user is in the midst of a battle
and
RAM 101 is completely filled with data representing the objects within view at
that moment, if the user moves the view rapidly to the left to view objects
that are
not presently loaded in RAM 101, a discontinuity in the action will result
since
there not be enough time to load the new objects from Hard Drive 103 or
Optical
Media 104 into RAM 101.
[0048] Another problem with the system of Figure 1 arises due to
limitations in the storage capacity of hard drives 103 and optical media 104.
Although disk storage devices can be manufactured with a relatively large
storage
capacity (e.g., 50 gigabytes or more), they still do not provide enough
storage
capacity for certain scenarios encountered in current video games. For
example,
as previously mentioned, a soccer video game might allow the user to choose
among dozens of teams, players and stadiums throughout the world. For each
team, each player and each stadium a large number of texture maps and
environment maps are needed to characterize the 3D surfaces in the world
(e.g.,
each team has a unique jersey, with each requiring a unique texture map).
[0049] One technique used to address this latter problem is for the game
to pre-compute texture and environment maps once they are selected by the
user.
This may involve a number of computationally-intensive processes, including
decompressing images, 3D mapping, shading, organizing data structures, etc. As
a result, there may be a delay for the user while the video game is performing
these calculations. On way to reduce this delay, in principle, is to perform
all of
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
these computations - including every permutation of team, player roster, and
stadium - when the game was originally developed. The released version of the
game would then include all of this pre-processed data stored on optical media
104, or on one or more servers on the Internet with just the selected pre-
processed
data for a given team, player roster, stadium selection downloaded through the
Internet to hard drive 103 when the user makes a selection. As a practical
matter,
however, such pre-loaded data of every permutation possible in game play could
easily be terabytes of data, which is far in excess of the capacity of today's
optical
media devices. Furthermore, the data for a given team, player roster, stadium
selection could easily be hundreds of megabytes of data or more. With a home
network connection of, say, 10Mbps, it would take longer to download this data
through network connection 105 than it would to compute the data locally.
[0050] Thus, the prior art game architecture shown in Figure 1 subjects
the user to significant delays between major scene transitions of complex
games.
[0051] Another problem with prior art approaches such as that shown in
Figure 1 is that over the years video games tend to become more advanced and
require more CPU/GPU processing power. Thus, even assuming an unlimited
amount of RAM, video games hardware requirements go beyond the peak level
of processing power available in these systems. As a result, users are
required to
upgrade gaming hardware every few years to keep pace (or play newer games at
lower quality levels). One consequence of the trend to ever more advanced
video
games is that video game playing machines for home use are typically
economically inefficient because their cost is usually determined by the
requirements of the highest performance game they can support. For example, an
XBox 360 might be used to play a game like "Gears of War", which demands a
high performance CPU, GPU, and hundreds of megabytes of RAM, or the XBox
360 might be used to play Pac Man, a game from the 1970s that requires only
kilobytes of RAM and a very low performance CPU. Indeed, an XBox 360 has
enough computing power to host many simultaneous Pac Man games at once.
26
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0052] Video games machines are typically turned off for most of the
hours of a week. According to a July 2006 Nielsen Entertainment study of
active
gamers 13 years and older, on average, active gamers spend fourteen hours/week
playing console video games, or just 12% of the total hours in a week. This
means that the average video game console is idle 88% of the time, which is an
inefficient use of an expensive resource. This is particularly significant
given that
video game consoles are often subsidized by the manufacturer to bring down the
purchase price (with the expectation that the subsidy will be earned back by
royalties from future video game software purchases).
[0053] Video game consoles also incur costs associated with almost any
consumer electronic device. For instance, the electronics and mechanisms of
the
systems need to be housed in an enclosure. The manufacturer needs to offer a
service warranty. The retailer who sells the system needs to collect a margin
on
either the sale of the system and/or on the sale of video game software. All
of
these factors add to the cost of the video game console, which must either be
subsidized by the manufacturer, passed along to the consumer, or both.
[0054] In addition, piracy is a major problem for the video game industry.
The security mechanisms utilized on virtually every major video gaming system
have been "cracked" over the years, resulting in unauthorized copying of video
games. For example, the Xbox 360 security system was cracked in July 2006
and users are now able to download illegal copies online. Games that are
downloadable (e.g., games for the PC or the Mac) are particularly vulnerable
to
piracy. In certain regions of the world where piracy is weakly policed there
is
essentially no viable market for standalone video game software because users
can buy pirated copies as readily as legal copies for a tiny fraction of the
cost.
Also, in many parts of the world the cost of a game console is such a high
percentage of income that even if piracy were controlled, few people could
afford
a state-of-the-art gaming system.
27
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0055] In addition, the used game market reduces revenue for the video
game industry. When a user has become tired of a game, they can sell the game
to a store which will resell the game to other users. This unauthorized but
common practice significantly reduces revenues of game publishers. Similarly,
a
reduction in sales on the order of 50% commonly occurs when there is a
platform
transition every few years. This is because users stop buying games for the
older
platforms when they know that the newer version platform is about to be
released
(e.g., when Playstation 3 is about to be released, users stop buying
Playstation 2
games). Combined, the loss of sales and increased development costs associated
with the new platforms can have a very significant adverse impact on the
profitability of game developers.
[0056] New game consoles are also very expensive. The Xbox 360, the
Nintendo Wii, and the Sony Playstation 3 all retail for hundreds of dollars.
High
powered personal computer gaming systems can cost up to $8000. This
represents a significant investment for users, particularly considering that
the
hardware becomes obsolete after a few years and the fact that many systems are
purchased for children.
[0057] One approach to the foregoing problems is online gaming in which
the gaming program code and data are hosted on a server and delivered to
client
machines on-demand as compressed video and audio streamed over a digital
broadband network. Some companies such as G-Cluster in Finland (now a
subsidiary of Japan's SOFTBANK Broadmedia) currently provide these services
online. Similar gaming services have become available in local networks, such
as
those within hotels and offered by DSL and cable television providers. A major
drawback of these systems is the problem of latency, i.e., the time it takes
for a
signal to travel to and from the game server, which is typically located in an
operator's "head-end". Fast action video games (also known as "twitch" video
games) require very low latency between the time the user performs an action
with the game controller and the time the display screen is updated showing
the
28
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
result of the user action. Low latency is needed so that the user has the
perception
that the game is responding "instantly". Users may be satisfied with different
latency intervals depending on the type of game and the skill level of the
user.
For example, I OOms of latency may be tolerable for a slow casual game (like
backgammon) or a slow-action role playing game, but in a fast action game a
latency in excess of 70 or 80ms may cause the user to perform more poorly in
the
game, and thus is unacceptable. For instance, in a game that requires fast
reaction
time there is a sharp decline in accuracy as latency increases from 50 to
100ms.
[0058] When a game or application server is installed in a nearby,
controlled network environment, or one where the network path to the user is
predictable and/or can tolerate bandwidth peaks, it is far easier to control
latency,
both in terms of maximum latency and in terms of the consistency of the
latency
(e.g., so the user observes steady motion from digital video streaming through
the
network). Such level of control can be achieved between a cable TV network
head-end to a cable TV subscriber's home, or from a DSL central office to DSL
subscriber's home, or in a commercial office Local Area Network (LAN)
environment from a server or a user. Also, it is possible to obtain specially-
graded
point-to-point private connections between businesses which have guaranteed
bandwidth and latency. But in a game or application system that hosts games in
a
server center connected to the general Internet and then streams compressed
video to the user through a broadband connection, latency is incurred from
many
factors, resulting in severe limitations in the deployment of prior art
systems.
[0059] In a typical broadband-connected home, a user may have a DSL or
cable modem for broadband service. Such broadband services commonly incur as
much as a 25ms round-trip latency (and at times more) between the user's home
and the general Internet. In addition, there are round-trip latencies incurred
from
routing data through the Internet to a server center. The latency through the
Internet varies based on the route that the data is given and the delays it
incurs as
it is routed. In addition to routing delays, round-trip latency is also
incurred due
29
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
to the speed of light traveling through the optical fiber that interconnects
most of
the Internet. For example, for each 1000 miles, approximately 22ms is incurred
in
round-trip latency due to the speed of light through the optical fiber and
other
overhead.
[0060] Additional latency can occur due to the data rate of the data
streamed through the Internet. For example, if a user has DSL service that is
sold
as "6Mbps DSL service", in practice, the user will probably get less than
5Mbps
of downstream throughput at best, and will likely see the connection degrade
periodically due to various factors such as congestion during peak load times
at
the Digital Subscriber Line Access Multiplexer (DSLAM). A similar issue can
occur reducing a the data rate of a cable modem is used for a connection sold
as
"6Mbps cable modem service" to far less than that, if there is congestion in
the
local shared coaxial cable looped through the neighborhood, or elsewhere in
the
cable modem system network. If data packets at a steady rate of 4Mbps are
streamed as one-way in User Datagram Protocol (UDP) format from a server
center through such connections, if everything is working well, the data
packets
will pass through without incurring additional latency, but if there is
congestion
(or other impediments) and only 3.5Mbps is available to stream data to the
user,
then in a typical situation either packets will be dropped, resulting in lost
data, or
packets will queue up at the point of congestion, until they can be sent,
thereby
introducing additional latency. Different points of congestion have different
queuing capacity to hold delayed packets, so in some cases packets that can't
make it through the congestion are dropped immediately. In other cases,
several
megabits of data are queued up and eventually be sent. But, in almost all
cases,
queues at points of congestion have capacity limits, and once those limits are
exceeded, the queues will overflow and packets will be dropped. Thus, to avoid
incurring additional latency (or worse, loss of packets), it is necessary to
avoid
exceeding the data rate capacity from the game or application server to the
user.
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[00611 Latency is also incurred by the time required to compress video in
the server and decompress video in the client device. Latency is further
incurred
while a video game running on a server is calculating the next frame to be
displayed. Currently available video compression algorithms suffer from either
high data rates or high latency. For example, motion JPEG is an intraframe-
only
lossy compression algorithm that is characterized by low-latency. Each frame
of
video is compressed independently of each other frame of video. When a client
device receives a frame of compressed motion JPEG video, it can immediately
decompress the frame and display it, resulting in very low latency. But
because
each frame is compressed separately, the algorithm is unable to exploit
similarities between successive frames, and as a result intraframe-only video
compression algorithms suffer from very high data rates. For example, 60 fps
(frames per second) 640x480 motion JPEG video may require 40Mbps (megabits
per second) or more of data. Such high data rates for such low resolution
video
windows would be prohibitively expensive in many broadband applications (and
certainly for most consumer Internet-based applications). Further, because
each
frame is compressed independently, artifacts in the frames that may result
from
the lossy compression are likely to appear in different places in successive
frames. This can results in what appears to the viewer as a moving visual
artifacts
when the video is decompressed.
[0062] Other compression algorithms, such as MPEG2, H.264 or VC9
from Microsoft Corporation as they are used in prior art configurations, can
achieve high compression ratios, but at the cost of high latency. Such
algorithms
utilize interframe as well as intraframe compression. Periodically, such
algorithms perform an intraframe-only compression of a frame. Such a frame is
known as a key frame (typically referred to as an "I" frame). Then, these
algorithms typically compare the I frame with both prior frames and successive
frames. Rather than compressing the prior frames and successive frames
independently, the algorithm determines what has changed in the image from the
31
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
I frame to the prior and successive frames, and then stores those changes as
what
are called "B" frames for the changes preceding the I frame and "P" frames for
the changes following the I frame. This results in much lower data rates than
intraframe-only compression. But, it typically comes at the cost of higher
latency.
An I frame is typically much larger than a B or P frame (often 10 times
larger),
and as a result, it takes proportionately longer to transmit at a given data
rate.
[0063] Consider, for example, a situation where the I frames are lOX the
size of B and P frames, and there are 29 B frames + 30 P frames = 59
interframes
for every single I intraframe, or 60 frames total for each "Group of Frames"
(GOP). So, at 60 fps, there is 1 60-frame GOP each second. Suppose the
transmission channel has a maximum data rate of 2Mbps. To achieve the highest
quality video in the channel, the compression algorithm would produce a 2Mbps
data stream, and given the above ratios, this would result in 2 Megabits (Mb)
/
(59+10) = 30,394 bits per intraframe and 303,935 bits per I frame. When the
compressed video stream is received by the decompression algorithm, in order
for
the video to play steadily, each frame needs to decompressed and displayed at
a
regular interval (e.g., 60 fps). To achieve this result, if any frame is
subject to
transmission latency, all of the frames need to be delayed by at least that
latency,
so the worst-case frame latency will define the latency for every video frame.
The
I frames introduce the longest transmission latencies since they are largest,
and an
entire I frame would have to be received before the I frame could be
decompressed and displayed (or any interframe dependent on the I frame). Given
that the channel data rate is 2Mbps, it will take 303,935/2Mb = 145ms to
transmit
an I frame.
[0064] An interframe video compression system as described above using
a large percentage of the bandwidth of the transmission channel will be
subject to
long latencies due to the large size of an I frame relative to the average
size of a
frame. Or, to put it another way, while prior art interframe compression
algorithms achieve a lower average per-frame data rate than intraframe-only
32
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
compression algorithms (e.g., 2Mbps vs. 40Mbps), they still suffer from a high
peak per-frame data rate (e.g., 303,935 * 60 = 18.2Mbps) because of the large
I
frames. Bear in mind, though that the above analysis assumes that the P and B
frames are all much smaller than the I frames. While this is generally true,
it is
not true for frames with high image complexity uncorrelated with the prior
frame,
high motion, or scene changes. In such situations, the P or B frames can
become
as large as I frames (if a P or B frame gets larger than an I frame, a
sophisticated
compression algorithm will typically "force" an I frame and replace the P or B
frame with an I frame). So, I frame-sized data rate peaks can occur at any
moment in a digital video stream. Thus, with compressed video, when the
average video data rate approaches data rate capacity of the transmission
channels
(as is frequently the case, given the high data rate demands for video) the
high
peak data rates from I frames or large P or B frames result in a high frame
latency.
[0065] Of course, the above discussion only characterizes the
compression algorithm latency created by large B, P or I frames in a GOP. If B
frames are used, the latency will be even higher. The reason why is because
before a B frame can be displayed, all of the B frames after the B frame and
the I
frame must be received. Thus, in a group of picture (GOP) sequence such as
BBBBBIPPPPPBBBBBIPPPPP, where there are 5 B frames before each I frame,
the first B frame can not be displayed by the video decompressor until the
subsequent B frames and I frame are received. So, if video is being streamed
at
60fps (i.e., 16.67ms/frame), before the first B frame can be decompressed,
five B
frames and the I frame will take 16.67 * 6 = I OOms to receive, no matter how
fast
the channel bandwidth is, and this is with just 5 B frames. Compressed video
sequences with 30 B frames are quite common. And, at a low channel bandwidth
like 2Mbps, the latency impact caused by the size of the I frame is largely
additive to the latency impact due to waiting for B frames to arrive. Thus, on
a
2Mbps channel, with a large number of B frames it is quite easy to exceed
500ms
33
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
of latency or more using prior art video compression technology. If B frames
are
not used (at the cost of a lower compression ratio for given quality level),
the B
frame latency is not incurred, but the latency caused by the peak frame sizes,
described above, is still incurred.
[0066] The problem is exacerbated by very the nature of many video
games. Video compression algorithms utilizing the GOP structure described
above have been largely optimized for use with live video or motion picture
material intended for passive viewing. Typically, the camera (whether a real
camera, or a virtual camera in the case of a computer-generated animation) and
scene is relatively steady, simply because if the camera or scene moves around
too jerkily, the video or movie material is (a) typically unpleasant to watch
and
(b) if it is being watched, usually the viewer is not closely following the
action
when the camera jerks around suddenly (e.g., if the camera is bumped when
shooting a child blowing out the candles on a birthday cake and suddenly jerks
away from the cake and back again, the viewers are typically focused on the
child
and the cake, and disregard the brief interruption when the camera suddenly
moves). In the case of a video interview, or a video teleconference, the
camera
may be held in a fixed position and not move at all, resulting in very few
data
peaks at all. But 3D high action video games are characterized by constant
motion
(e.g., consider a 3D racing, where the entire frame is in rapid motion for the
duration of the race, or consider first-person shooters, where the virtual
camera is
constantly moving around jerkily). Such video games can result in frame
sequences with large and frequent peaks where the user may need to clearly see
what is happening during those sudden motions. As such, compression artifacts
are far less tolerable in 3D high action video games. Thus, the video output
of
many video games, by their nature, produces a compressed video stream with
very high and frequent peaks.
[0067] Given that users of fast-action video games have little tolerance for
high latency, and given all of the above causes of latency, to date there have
been
34
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
limitations to server-hosted video games that stream video on the Internet.
Further, users of applications that require a high degree of interactivity
suffer
from similar limitations if the applications are hosted on the general
Internet and
stream video. Such services require a network configuration in which the
hosting
servers are set up directly in a head end (in the case of cable broadband) or
the
central office (in the case of Digital Subscriber Lines (DSL)), or within a
LAN
(or on a specially-graded private connection) in a commercial setting, so that
the
route and distance from the client device to the server is controlled to
minimize
latency and peaks can be accommodated without incurring latency. LANs
(typically rated at 100Mbps-1Gbps) and leased lines with adequate bandwidth
typically can support peak bandwidth requirements (e.g., 18Mbps peak
bandwidth is a small fraction of a 100Mbps LAN capacity).
[0068] Peak bandwidth requirements can also be accommodated by
residential broadband infrastructure if special accommodations are made. For
example, on a cable TV system, digital video traffic can be given dedicated
bandwidth which can handle peaks, such as large I frames. And, on a DSL
system, a higher speed DSL modem can be provisioned, allowing for high peaks,
or a specially-graded connection can provisioned which can handle a higher
data
rates. But, conventional cable modem and DSL infrastructure attached to the
general Internet have far less tolerance for peak bandwidth requirements for
compressed video. So, online services that host video games or applications in
server centers a long distance from the client devices, and then stream the
compressed video output over the Internet through conventional residential
broadband connections suffer from significant latency and peak bandwidth
limitations - particularly with respect to games and applications which
require
very low latency (e.g., first person shooters and other multi-user,
interactive
action games, or applications requiring a fast response time).
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
BRIEF DESCRIPTION OF THE DRAWINGS
[0069] The present disclosure will be understood more fully from the
detailed description that follows and from the accompanying drawings, which
however, should not be taken to limit the disclosed subject matter to the
specific
embodiments shown, but are for explanation and understanding only.
[0070] FIG. 1 illustrates an architecture of a prior art video gaming
system.
[0071] FIGS. 2a-b illustrate a high level system architecture according to
one embodiment.
[0072] FIG. 3 illustrates actual, rated, and required data rates for
communication between a client and a server.
[0073] FIG. 4a illustrates a hosting service and a client employed
according to one embodiment.
[0074] FIG. 4b illustrates exemplary latencies associated with
communication between a client and hosting service.
[0075] FIG 4c illustrates a client device according to one embodiment.
[0076] FIG 4d illustrates a client device according to another
embodiment.
[0077] FIG 4e illustrates an example block diagram of the client device in
Figure 4c.
[0078] FIG 4f illustrates an example block diagram of the client device in
Figure 4d.
[0079] FIG. 5 illustrates an example form of video compression which
may be employed according to one embodiment.
36
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0080] FIG. 6a illustrates an example form of video compression which
may be employed in another embodiment.
[00811 FIG. 6b illustrates peaks in data rate associated with transmitting a
low complexity, low action video sequence.
[0082] FIG. 6c illustrates peaks in data rate associated with transmitting a
high complexity, high action video sequence.
[0083] FIGS. 7a-b illustrate example video compression techniques
employed in one embodiment.
[0084] FIG. 8 illustrates additional example video compression
techniques employed in one embodiment.
[0085] FIGS. 9a-c illustrate example techniques employed in one
embodiment for alleviating data rate peaks.
[0086] FIGS. 10a-b illustrate one embodiment which efficiently packs
image tiles within packets.
[0087] FIGS. lla-d illustrate embodiments which employ forward error
correction techniques.
[0088] FIG. 12 illustrates one embodiment which uses multi-core
processing units for compression.
[0089] FIGS. 13a-b illustrate geographical positioning and
communication between hosting services according to various embodiments.
[0090] FIG. 14 illustrates exemplary latencies associated with
communication between a client and a hosting service.
37
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0091 ] FIG. 15 illustrates an example hosting service server center
architecture.
[0092] FIG. 16 illustrates an example screen shot of one embodiment of a
user interface which includes a plurality of live video windows.
[0093] FIG. 17 illustrates the user interface of Figure 16 following the
selection of a particular video window.
[0094] FIG. 18 illustrates the user interface of Figure 17 following
zooming of the particular video window to full screen size.
[0095] FIG. 19 illustrates an example collaborative user video data
overlaid on the screen of a multiplayer game.
[0096] FIG. 20 illustrates an example user page for a game player on a
hosting service.
[0097] FIG. 21 illustrates an example 3D interactive advertisement.
[0098] FIG. 22 illustrates an example sequence of steps for producing a
photoreal image having a textured surface from surface capture of a live
performance.
[0099] FIG. 23 illustrates an example user interface page that allows for
selection of linear media content.
[0100] FIG. 24 is a graph that illustrates the amount of time that elapses
before the web page is live versus connection speed.
DESCRIPTION OF EXAMPLE EMBODIMENTS
[0101] In the following description specific details are set forth, such as
device types, system configurations, communication methods, etc., in order to
38
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
provide a thorough understanding of the present disclosure. However, persons
having ordinary skill in the relevant arts will appreciate that these specific
details
may not be needed to practice the embodiments described.
[0102] Figures 2a-b provide a high-level architecture of two embodiments
in which video games and software applications are hosted by a hosting service
210 and accessed by client devices 205 at user premises 211 (note that the
"user
premises" means the place wherever the user is located, including outdoors if
using a mobile device) over the Internet 206 (or other public or private
network)
under a subscription service. The client devices 205 may be general-purpose
computers such as Microsoft Windows- or Linux-based PCs or Apple, Inc.
Macintosh computers with a wired or wireless connection to the Internet either
with internal or external display device 222, or they may be dedicated client
devices such as a set-top box (with a wired or wireless connection to the
Internet)
that outputs video and audio to a monitor or TV set 222, or they may be mobile
devices, presumably with a wireless connection to the Internet.
[0103] Any of these devices may have their own user input devices (e.g.,
keyboards, buttons, touch screens, track pads or inertial-sensing wands, video
capture cameras and/or motion-tracking cameras, etc.), or they may use
external
input devices 221 (e.g., keyboards, mice, game controllers, inertial sensing
wand,
video capture cameras and/or motion tracking cameras, etc.), connected with
wires or wirelessly. As described in greater detail below, the hosting service
210
includes servers of various levels of performance, including those with high-
powered CPU/GPU processing capabilities. During playing of a game or use of
an application on the hosting service 210, a home or office client device 205
receives keyboard and/or controller input from the user, and then it transmits
the
controller input through the Internet 206 to the hosting service 210 that
executes
the gaming program code in response and generates successive frames of video
output (a sequence of video images) for the game or application software
(e.g., if
the user presses a button which would direct a character on the screen to move
to
39
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
the right, the game program would then create a sequence of video images
showing the character moving to the right). This sequence of video images is
then compressed using a low-latency video compressor, and the hosting service
210 then transmits the low-latency video stream through the Internet 206. The
home or office client device then decodes the compressed video stream and
renders the decompressed video images on a monitor or TV. Consequently, the
computing and graphical hardware requirements of the client device 205 are
significantly reduced. The client 205 only needs to have the processing power
to
forward the keyboard/controller input to the Internet 206 and decode and
decompress a compressed video stream received from the Internet 206, which
virtually any personal computer is capable of doing today in software on its
CPU
(e.g., a Intel Corporation Core Duo CPU running at approximately 2GHz is
capable of decompressing 720p HDTV encoded using compressors such as H.264
and Windows Media VC9). And, in the case of any client devices, dedicated
chips can also perform video decompression for such standards in real-time at
far
lower cost and with far less power consumption than a general-purpose CPU such
as would be required for a modern PC. Notably, to perform the function of
forwarding controller input and decompressing video, home client devices 205
do
not require any specialized graphics processing units (GPUs), optical drive or
hard drives, such as the prior art video game system shown in Figure 1.
[0104] As games and applications software become more complex and
more photo-realistic, they will require higher-performance CPUs, GPUs, more
RAM, and larger and faster disk drives, and the computing power at the hosting
service 210 may be continually upgraded, but the end user will not be required
to
update the home or office client platform 205 since its processing
requirements
will remain constant for a display resolution and frame rate with a given
video
decompression algorithm. Thus, the hardware limitations and compatibility
issues seen today do not exist in the system illustrated in Figures 2a-b.
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0105] Further, because the game and application software executes only
in servers in the hosting service 210, there never is a copy of the game or
application software (either in the form of optical media, or as downloaded
software) in the user's home or office ("office" as used herein unless
otherwise
qualified shall include any non-residential setting, including, schoolrooms,
for
example). This significantly mitigates the likelihood of a game or application
software being illegally copied (pirated), as well as mitigating the
likelihood of a
valuable database that might be use by a game or applications software being
pirated. Indeed, if specialized servers are required (e.g., requiring very
expensive,
large or noisy equipment) to play the game or application software that are
not
practical for home or office use, then even if a pirated copy of the game or
application software were obtained, it would not be operable in the home or
office.
[0106] In one embodiment, the hosting service 210 provides software
development tools to the game or application software developers (which refers
generally to software development companies, game or movie studios, or game or
applications software publishers) 220 which design video games so that they
may
design games capable of being executed on the hosting service 210. Such tools
allow developers to exploit features of the hosting service that would not
normally be available in a standalone PC or game console (e.g., fast access to
very large databases of complex geometry ("geometry" unless otherwise
qualified
shall be used herein to refer to polygons, textures, rigging, lighting,
behaviors and
other components and parameters that define 3D datasets)).
[0107] Different business models are possible under this architecture.
Under one model, the hosting service 210 collects a subscription fee from the
end
user and pays a royalty to the developers 220, as shown in Figure 2a. In an
alternate implementation, shown in Figure 2b, the developers 220 collects a
subscription fee directly from the user and pays the hosting service 210 for
hosting the game or application content. These underlying principles are not
41
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
limited to any particular business model for providing online gaming or
application hosting.
[0108] COMPRESSED VIDEO CHARACTERISTICS
[0109] As discussed previously, one significant problem with providing
video game services or applications software services online is that of
latency. A
latency of 70-80ms(from the point a input device is actuated by the user to
the
point where a response is displayed on the display device) is at the upper
limit for
games and applications requiring a fast response time. However, this is very
difficult to achieve in the context of the architecture shown in Figures 2a
and 2b
due to a number of practical and physical constraints.
[0110] As indicated in Figures 3, when a user subscribes to an Internet
service, the connection is typically rated by a nominal maximum data rate 301
to
the user's home or office. Depending on the provider's policies and routing
equipment capabilities, that maximum data rate may be more or less strictly
enforced, but typically the actual available data rate is lower for one of
many
different reasons. For example, there may be too much network traffic at the
DSL central office or on the local cable modem loop, or there may be noise on
the cabling causing dropped packets, or the provider may establish a maximum
number of bits per month per user. Currently, the maximum downstream data rate
for cable and DSL services typically ranges from several hundred
Kilobits/second
(Kbps) to 30 Mbps. Cellular services are typically limited to hundreds of Kbps
of
downstream data. However, the speed of the broadband services and the number
of users who subscribe to broadband services will increase dramatically over
time. Currently, some analysts estimate that 33% of US broadband subscribers
have a downstream data rate of 2Mbps or more. For example, some analysts
predict that by 2010, over 85% of US broadband subscribers will have a data
rate
of 2Mbps or more.
[0111] As indicated in Figure 3, the actual available max data rate 302
may fluctuate over time. Thus, in a low-latency, online gaming or application
42
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
software context it is sometimes difficult to predict the actual available
data rate
for a particular video stream. If the data rate 303 required to sustain a
given level
of quality at given number of frames-per-second (fps) at a given resolution
(e.g.,
640 x 480 @ 60 fps) for a certain amount of scene complexity and motion rises
above the actual available max data rate 302 (as indicated by the peak in
Figure
3), then several problems may occur. For example, some internet services will
simply drop packets, resulting in lost data and distorted/lost images on the
user's
video screen. Other services will temporarily buffer (i.e., queue up) the
additional packets and provide the packets to the client at the available data
rate,
resulting in an increase in latency - an unacceptable result for many video
games
and applications. Finally, some Internet service providers will view the
increase
in data rate as a malicious attack, such as a denial of service attack (a well
known
technique user by hackers to disable network connections), and will cut off
the
user's Internet connection for a specified time period. Thus, the embodiments
described herein take steps to ensure that the required data rate for a video
game
does not exceed the maximum available data rate.
[0112] HOSTING SERVICE ARCHITECTURE
[0113] Figure 4a illustrates an architecture of the hosting service 210
according to one embodiment. The hosting service 210 can either be located in
a
single server center, or can be distributed across a plurality of server
centers (to
provide for lower latency connections to users that have lower latency paths
to
certain server centers than others, to provide for load balancing amongst
users,
and to provide for redundancy in the case one or more server centers fail).
The
hosting service 210 may eventually include hundreds of thousands or even
millions of servers 402, serving a very large user base. A hosting service
control
system 401 provides overall control for the hosting service 210, and directs
routers, servers, video compression systems, billing and accounting systems,
etc.
In one embodiment, the hosting service control system 401 is implemented on a
distributed processing Linux-based system tied to RAID arrays used to store
the
43
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
databases for user information, server information, and system statistics. In
the
foregoing descriptions, the various actions implemented by the hosting service
210, unless attributed to other specific systems, are initiated and controlled
by the
hosting service control system 401.
[0114] The hosting service 210 includes a number of servers 402 such as
those currently available from Intel, IBM and Hewlett Packard, and others.
Alternatively, the servers 402 can be assembled in a custom configuration of
components, or can eventually be integrated so an entire server is implemented
as
a single chip. Although this diagram shows a small number of servers 402 for
the
sake of illustration, in an actual deployment there may be as few as one
server
402 or as many as millions of servers 402 or more. The servers 402 may all be
configured in the same way (as an example of some of the configuration
parameters, with the same CPU type and performance; with or without a GPU,
and if with a GPU, with the same GPU type and performance; with the same
number of CPUs and GPUs; with the same amount of and type/speed of RAM;
and with the same RAM configuration), or various subsets of the servers 402
may
have the same configuration (e.g., 25% of the servers can be configured a
certain
way, 50% a different way, and 25% yet another way), or every server 402 may be
different.
[0115] In one embodiment, the servers 402 are diskless, i.e., rather than
having its own local mass storage (be it optical or magnetic storage, or
semiconductor-based storage such as Flash memory or other mass storage means
serving a similar function), each server accesses shared mass storage through
fast
backplane or network connection. In one embodiment, this fast connection is a
Storage Area Network (SAN) 403 connected to a series of Redundant Arrays of
Independent Disks (RAID) 405 with connections between devices implemented
using Gigabit Ethernet. As is known by those of skill in the art, a SAN 403
may
be used to combine many RAID arrays 405 together, resulting in extremely high
bandwidth-approaching or potentially exceeding the bandwidth available from
44
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
the RAM used in current gaming consoles and PCs. And, while RAID arrays
based on rotating media, such as magnetic media, frequently have significant
seek-time access latency, RAID arrays based on semiconductor storage can be
implemented with much lower access latency. In another configuration, some or
all of the servers 402 provide some or all of their own mass storage locally.
For
example, a server 402 may store frequently-accessed information such as its
operating system and a copy of a video game or application on low-latency
local
Flash-based storage, but it may utilize the SAN to access RAID Arrays 405
based
on rotating media with higher seek latency to access large databases of
geometry
or game state information on a less frequent bases.
[0116] In addition, in one embodiment, the hosting service 210 employs
low-latency video compression logic 404 described in detail below. The video
compression logic 404 may be implemented in software, hardware, or any
combination thereof (certain embodiments of which are described below). Video
compression logic 404 includes logic for compressing audio as well as visual
material.
[0117] In operation, while playing a video game or using an application at
the user premises 211 via a keyboard, mouse, game controller or other input
device 421, control signal logic 413 on the client 415 transmits control
signals
406a-b (typically in the form of UDP packets) representing the button presses
(and other types of user inputs) actuated by the user to the hosting service
210.
The control signals from a given user are routed to the appropriate server (or
servers, if multiple servers are responsive to the user's input device) 402.
As
illustrated in Figure 4a, control signals 406a may be routed to the servers
402 via
the SAN. Alternatively or in addition, control signals 406b may be routed
directly to the servers 402 over the hosting service network (e.g., an
Ethernet-
based local area network). Regardless of how they are transmitted, the server
or
servers execute the game or application software in response to the control
signals
406a-b. Although not illustrated in Figure 4a, various networking components
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
such as a firewall(s) and/or gateway(s) may process incoming and outgoing
traffic at the edge of the hosting service 210 (e.g., between the hosting
service
210 and the Internet 410) and/or at the edge of the user premises 211 between
the
Internet 410 and the home or office client 415. The graphical and audio output
of
the executed game or application software- i.e., new sequences of video
images-are provided to the low-latency video compression logic 404 which
compresses the sequences of video images according to low-latency video
compression techniques, such as those described herein and transmits a
compressed video stream, typically with compressed or uncompressed audio,
back to the client 415 over the Internet 410 (or, as described below, over an
optimized high speed network service that bypasses the general Internet). Low-
latency video decompression logic 412 on the client 415 then decompresses the
video and audio streams and renders the decompressed video stream, and
typically plays the decompressed audio stream, on a display device 422
Alternatively, the audio can be played on speakers separate from the display
device 422 or not at all. Note that, despite the fact that input device 421
and
display device 422 are shown as free-standing devices in Figures 2a and 2b,
they
may be integrated within client devices such as portable computers or mobile
devices.
[0118] Home or office client 415 (described previously as home or office
client 205 in Figures 2a and 2b) may be a very inexpensive and low-power
device, with very limited computing or graphics performance and may well have
very limited or no local mass storage. In contrast, each server 402, coupled
to a
SAN 403 and multiple RAIDs 405 can be an exceptionally high performance
computing system, and indeed, if multiple servers are used cooperatively in a
parallel-processing configuration, there is almost no limit to the amount of
computing and graphics processing power that can be brought to bear. And,
because of the low-latency video compression 404 and low-latency video
compression 412, perceptually to the user, the computing power of the servers
46
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
402 is being provided to the user. When the user presses a button on input
device
421, the image on display 422 is updated in response to the button press
perceptually with no meaningful delay, as if the game or application software
were running locally. Thus, with a home or office client 415 that is a very
low
performance computer or just an inexpensive chip that implements the low-
latency video decompression and control signal logic 413, a user is provided
with
effectively arbitrary computing power from a remote location that appears to
be
available locally. This gives users the power to play the most advanced,
processor-intensive (typically new) video games and the highest performance
applications.
[0119] Figure 4c shows a very basic and inexpensive home or office
client device 465. This device is an embodiment of home or office client 415
from Figures 4a and 4b. It is approximately 2 inches long. It has an Ethernet
jack
462 that interfaces with an Ethernet cable with Power over Ethernet (PoE),
from
which it derives its power and its connectivity to the Internet. It is able to
run
Network Address Translation (NAT) within a network that supports NAT. In an
office environment, many new Ethernet switches have PoE and bring PoE
directly to a Ethernet jack in an office. It such a situation, all that is
required is an
Ethernet cable from the wall jack to the client 465. If the available Ethernet
connection does not carry power (e.g., in a home with a DSL or cable modem,
but
no PoE), then there are inexpensive wall "bricks" (i.e., power supplies)
available
that will accept an unpowered Ethernet cable and output Ethernet with PoE.
[0120] The client 465 contains control signal logic 413 (of Figure 4a)
that is coupled to a Bluetooth wireless interface, which interfaces with
Bluetooth
input devices 479, such as a keyboard, mouse, game controller and/or
microphone and/or headset. Also, one embodiment of client 465 is capable of
outputting video at 120fps coupled with a display device 468 able to support
120fps video and signal (typically through infrared) a pair of shuttered
glasses
466 to alternately shutter one eye, then the other with each successive frame.
The
47
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
effect perceived by the user is that of a stereoscopic 3D image that "jumps
out" of
the display screen. One such display device 468 that supports such operation
is
the Samsung HL-T5076S. Since the video stream for each eye is separate, in one
embodiment two independent video streams are compressed by the hosting
service 210, the frames are interleaved in time, and the frames are
decompressed
as two independent decompression processes within client 465.
[0121] The client 465 also contains low latency video decompression
logic 412, which decompresses the incoming video and audio and output through
the HDMI (High-Definition Multimedia Interface),connector 463 which plugs
into an SDTV (Standard Definition Television) or HDTV (High Definition
Television) 468, providing the TV with video and audio, or into a monitor 468
that supports HDMI. If the user's monitor 468 does not support HDMI, then an
HDMI-to-DVI (Digital Visual Interface) can be used, but the audio will be
lost.
Under the HDMI standard, the display capabilities (e.g. supported resolutions,
frame rates) 464 are communicated from the display device 468, and this
information is then passed back through the Internet connection 462 back to
the
hosting service 210 so it can stream compressed video in a format suitable for
the
display device.
[0122] Figure 4d shows a home or office client device 475 that is the
same as the home or office client device 465 shown in Figure 4c except that is
has
more external interfaces. Also, client 475 can accept either PoE for power, or
it
can run off of an external power supply adapter (not shown) that plugs in the
wall. Using client 475 USB input, video camera 477 provides compressed video
to client 475, which is uploaded by client 475 to hosting service 210 for use
described below. Built into camera 477 is a low-latency compressor utilizing
the
compression techniques described below.
[0123] In addition to having an Ethernet connector for its Internet
connection, client 475 also has an 802.11g wireless interface to the Internet.
Both
interfaces are able to use NAT within a network that supports NAT.
48
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0124] Also, in addition to having an HDMI connector to output video
and audio, client 475 also has a Dual Link DVI-I connector, which includes
analog output (and with a standard adapter cable will provide VGA output). It
also has analog outputs for composite video and S-video.
[0125] For audio, the client 475 has left/right analog stereo RCA jacks,
and for digital audio output it has a TOSLINK output.
[0126] In addition to a Bluetooth wireless interface to input devices 479,
it also has USB jacks to interface to input devices.
[0127] Figure 4e shows one embodiment of the internal architecture of
client 465. Either all or some of the devices shown in the diagram can be
implemented in an Field Programmable Logic Array, an custom ASIC or in
several discrete devices, either custom designed or off-the-shelf.
[0128] Ethernet with PoE 497 attaches to Ethernet Interface 481. Power
499 is derived from the Ethernet with PoE 497 and is connected to the rest of
the
devices in the client 465. Bus 480 is a common bus for communication between
devices.
[0129] Control CPU 483 (almost any small CPU, such as a MIPS R4000
series CPU at 100MHz with embedded RAM is adequate) running a small client
control application from Flash 476 implements the protocol stack for the
network
(i.e. Ethernet interface) and also communicates with the Hosting Service 210,
and
configures all of the devices in the client 465. It also handles interfaces
with the
input devices 469 and sends packets back to the hosting service 210 with user
controller data, protected by Forward Error Correction, if necessary. Also,
Control CPU 483 monitors the packet traffic (e.g. if packets are lost or
delayed
and also timestamps their arrival). This information is sent back to the
hosting
service 210 so that it can constantly monitor the network connection and
adjust
what it sends accordingly. Flash memory 476 is initially loaded at the time of
manufacture with the control program for Control CPU 483 and also with a
serial
49
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
number that is unique to the particular Client 465 unit. This serial number
allows
the hosting service 210 to uniquely identify the Client 465 unit.
[0130] Bluetooth interface 484 communicates to input devices 469
wirelessly through its antenna, internal to client 465.
[01311 Video decompressor 486 is a low-latency video decompressor
configured to implement the video decompression described herein. A large
number of video decompression devices exist, either off-the-shelf, or as
Intellectual Property (IP) of a design that can be integrated into an FPGA or
a
custom ASIC. One company offering IP for an H.264 decoder is Ocean Logic of
Manly, NSW Australia. The advantage of using IP is that the compression
techniques used herein do not conform to compression standards. Some standard
decompressors are flexible enough to be configured to accommodate the
compression techniques herein, but some can not. But, with IP, there is
complete
flexibility in redesigning the decompressor as needed.
[0132] The output of the video decompressor is coupled to the video
output subsystem 487, which couples the video to the video output of the HDMI
interface 490.
[0133] The audio decompression subsystem 488 is implemented either
using a standard audio decompressor that is available, or it can be
implemented as
IP, or the audio decompression can be implemented within the control processor
483 which could, for example, implement the Vorbis audio decompressor.
[0134] The device that implements the audio decompression is coupled to
the audio output subsystem 489 that couples the audio to the audio output of
the
HDMI interface 490
[0135] Figure 4f shows one embodiment of the internal architecture of
client 475. As can be seen, the architecture is the same as that of client 465
except
for additional interfaces and optional external DC power from a power supply
adapter that plugs in the wall, and if so used, replaces power that would come
from the Ethernet PoE 497. The functionality that is in common with client 465
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
will not be repeated below, but the additional functionality is described as
follows.
[0136] CPU 483 communicates with and configures the additional
devices.
[0137] WiFi subsystem 482 provides wireless Internet access as an
alternative to Ethernet 497 through its antenna. WiFi subsystems are available
from a wide range of manufacturers, including Atheros Communications of Santa
Clara, CA.
[0138] USB subsystem 485 provides an alternative to Bluetooth
communication for wired USB input devices 479. USB subsystems are quite
standard and readily available for FPGAs and ASICs, as well as frequently
built
into off-the-shelf devices performing other functions, like video
decompression.
[0139] Video output subsystem 487 produces a wider range of video
outputs than within client 465. In addition to providing HDMI 490 video
output,
it provides DVI-I 491, S-video 492, and composite video 493. Also, when the
DVI-I 491 interface is used for digital video, display capabilities 464 are
passed
back from the display device to the control CPU 483 so that it can notify the
hosting service 210 of the display device 478 capabilities. All of the
interfaces
provided by the video output subsystem 487 are quite standard interfaces and
readily available in many forms.
[0140] Audio output subsystem 489 outputs audio digitally through
digital interface 494 (S/PDIF and/or Toslink) and audio in analog form through
stereo analog interface 495.
[0141] ROUND-TRIP LATENCY ANALYSIS
[0142] Of course, for the benefits of the preceding paragraph to be
realized, the round trip latency between a user's action using input device
421 and
seeing the consequence of that action on display device 420 should be no more
than 70-80ms. This latency must take into account all of the factors in the
path
from input device 421 in the user premises 211 to hosting service 210 and back
51
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
again to the user premises 211 to display device 422. Figure 4b illustrates
the
various components and networks over which signals must travel, and above
these components and networks is a timeline that lists exemplary latencies
that
can be expected in a practical implementation. Note that Figure 4b is
simplified
so that only the critical path routing is shown. Other routing of data used
for
other features of the system is described below. Double-headed arrows (e.g.,
arrow 453) indicate round-trip latency and a single-headed arrow (e.g., arrow
457) indicate one-way latency, and "-" denote an approximate measure. It
should
be pointed out that there will be real-world situations where the latencies
listed
can not be achieved, but in a large number of cases in the US, using DSL and
cable modem connections to the user premises 211, these latencies can be
achieved in the circumstances described in the next paragraph. Also, note
that,
while cellular wireless connectivity to the Internet will certainly work in
the
system shown, most current US cellular data systems (such as EVDO) incur very
high latencies and would not be able to achieve the latencies shown in Figure
4b.
However, these underlying principles may be implemented on future cellular
technologies that may be capable of implementing this level of latency.
[0143] Starting from the input device 421 at user premises 211, once the
user actuates the input device 421, a user control signal is sent to client
415
(which may be a standalone device such a set-top box, or it may be software or
hardware running in another device such as a PC or a mobile device), and is
packetized (in UDP format in one embodiment) and the packet is given a
destination address to reach hosting service 210. The packet will also contain
information to indicate which user the control signals are coming from. The
control signal packet(s) are then forwarded through Firewall/Router/NAT
(Network Address Translation) device 443 to WAN interface 442. WAN
interface 442 is the interface device provided to the user premises 211 by the
User's ISP (Internet Service Provider). The WAN interface 442 may be a Cable
or DSL modem, a WiMax transceiver, a Fiber transceiver, a Cellular data
52
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
interface, an Internet Protocol-over-powerline interface, or any other of many
interfaces to the Internet. Further, Firewall/Router/NAT device 443 (and
potentially WAN interface 442) may be integrated into the client 415. An
example of this would be a mobile phone, which includes software to implement
the functionality of home or office client 415, as well as the means to route
and
connect to the Internet wirelessly through some standard (e.g., 802.11g).
[0144] WAN Interface 442 then routes the control signals to what shall be
called herein the "point of presence" 441 for the user's Internet Service
Provider
(ISP) which is the facility that provides an interface between the WAN
transport
connected to the user premises 211 and the general Internet or private
networks.
The point of presence's characteristics will vary depending upon nature of the
Internet service provided. For DSL, it typically will be a telephone company
Central Office where a DSLAM is located. For cable modems, it typically will
be
a cable Multi-System Operator (MSO) head end. For cellular systems, it
typically
will be a control room associated with cellular tower. But whatever the point
of
presence's nature, it will then route the control signal packet(s) to the
general
Internet 410. The control signal packet(s) will then be routed to the WAN
Interface 441 to the hosting service 210, through what most likely will be a
fiber
transceiver interface. The WAN 441 will then route the control signal packets
to
routing logic 409 (which may be implemented in many different ways, including
Ethernet switches and routing servers), which evaluates the user's address and
routes the control signal(s) to the correct server 402 for the given user.
[0145] The server 402 then takes the control signals as input for the game
or application software that is running on the server 402 and uses the control
signals to process the next frame of the game or application. Once the next
frame
is generated, the video and audio is output from server 402 to video
compressor
404. The video and audio may be output from server 402 to compressor 404
through various means. To start with, compressor 404 may be built into server
402, so the compression may be implemented locally within server 402. Or, the
53
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
video and/or audio may be output in packetized form through a network
connection such as an Ethernet connection to a network that is either a
private
network between server 402 and video compressor 404, or a through a shared
network, such as SAN 403. Or, the video may be output through a video output
connector from server 402, such as a DVI or VGA connector, and then captured
by video compressor 404. Also, the audio may be output from server 402 as
either digital audio (e.g., through a TOSLINK or S/PDIF connector) or as
analog
audio, which is digitized and encoded by audio compression logic within video
compressor 404.
[0146] Once video compressor 404 has captured the video frame and the
audio generated during that frame time from server 402, then video compressor
will compress the video and audio using techniques described below. Once the
video and audio is compressed it is packetized with an address to send it back
to
the user's client 415, and it is routed to the WAN Interface 441, which then
routes
the video and audio packets through the general Internet 410, which then
routes
the video and audio packets to the user's ISP point of presence 441, which
routes
the video and audio packets to the WAN Interface 442 at the user's premises,
which routes the video and audio packets to the Firewall/Router/NAT device
443,
which then routes the video and audio packets to the client 415.
[0147] The client 415 decompresses the video and audio, and then
displays the video on the display device 422 (or the client's built-in display
device) and sends the audio to the display device 422 or to separate
amplifier/speakers or to an amplifier/speakers built in the client.
[0148] For the user to perceive that the entire process just described is
perceptually without lag, the round-trip delay needs be less than 70 or 80ms.
Some of the latency delays in the described round-trip path are under the
control
of the hosting service 210 and/or the user and others are not. Nonetheless,
based
on analysis and testing of a large number of real-world scenarios, the
following
are approximate measurements.
54
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0149] The one-way transmission time to send the control signals 451 is
typically less than lms, the roundtrip routing through the user premises 452
is
typically accomplished, using readily available consumer-grade
Firewall/Router/NAT switches over Ethernet in about lms. User ISPs vary
widely in their round trip delays 453, but with DSL and cable modem providers,
we typically see between 10 and 25ms. The round trip latency on the general
Internet 410 can vary greatly depending on how traffic is routed and whether
there are any failures on the route (and these issues are discussed below),
but
typically the general Internet provides fairly optimal routes and the latency
is
largely determined by speed of light through optical fiber, given the distance
to
the destination. As discussed further below, we have established 1000 miles as
a
roughly the furthest distance that we expect to place a hosting service 210
away
from user premises 211. At 1000 miles (2000 miles round trip) the practical
transit time for a signal through the Internet is approximately 22ms. The WAN
Interface 441 to the hosting service 210 is typically a commercial-grade fiber
high
speed interface with negligible latency. Thus, the general Internet latency
454 is
typically between 1 and IOms. The one-way routing 455 latency through the
hosting service 210 can be achieved in less than lms. The server 402 will
typically compute a new frame for a game or an application in less than one
frame time (which at 60fps is 16.7ms) so l6ms is a reasonable maximum one-
way latency 456 to use. In an optimized hardware implementation of the video
compression and audio compression algorithms described herein, the
compression 457 can be completed in lms. In less optimized versions, the
compression may take as much as 6ms (of course even less optimized versions
could take longer, but such implementations would impact the overall latency
of
the round trip and would require other latencies to be shorter (e.g., the
allowable
distance through the general Internet could be reduced) to maintain the 70-
80ms
latency target). The round trip latencies of the Internet 454, User ISP 453,
and
User Premises Routing 452 have already been considered, so what remains is the
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
video decompression 458 latency which, depending on whether the video
decompression 458 is implemented in dedicated hardware, or if implemented in
software on a client device 415 (such as a PC or mobile device) it can vary
depending upon the size of the display and the performance of the
decompressing
CPU. Typically, decompression 458 takes between 1 and 8ms.
[0150] Thus, by adding together all of the worst-case latencies seen in
practice, we can determine the worst-case round trip latency that can be
expected
to be experience by a user of the system shown in Figure 4a. They are:
1+1+25+22+1+16+6+8 = 80ms. And, indeed, in practice (with caveats discussed
below), this is roughly the round trip latency seen using prototype versions
of the
system shown in Figure 4a, using off-the-shelf Windows PCs as client devices
and home DSL and cable modem connections within the US. Of course, scenarios
better than worst case can result in much shorter latencies, but they can not
be
relied upon in developing a commercial service that is used widely.
[0151] To achieve the latencies listed in Figures 4b over the general
Internet, requires the video compressor 404 and video decompressor 412 from
Figure 4a in the client 415 to generate a packet stream which very particular
characteristics, such that the packet sequence generated through entire path
from
the hosting service 210 to the display device 422 is not subject to delays or
excessive packet loss and, in particular, consistently falls with the
constraints of
the bandwidth available to the user over the user's Internet connection
through
WAN interface 442 and Firewall/Router/NAT 443. Further, the video compressor
must create a packet stream which is sufficiently robust so that it can
tolerate the
inevitable packet loss and packet reordering that occurs in normal Internet
and
network transmissions.
[0152] LOW-LATENCY VIDEO COMPRESSION
[0153] To accomplish the foregoing goals, one embodiment takes a new
approach to video compression which decreases the latency and the peak
bandwidth requirements for transmitting video. Prior to the description of
these
56
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
embodiments, an analysis of current video compression techniques will be
provided with respect to Figure 5 and Figures 6a-b. Of course, these
techniques
may be employed in accordance with underlying principles if the user is
provided
with sufficient bandwidth to handle the data rate required by these
techniques.
Note that audio compression is not addressed herein other than to state that
it is
implemented simultaneously and in synchrony with the video compression. Prior
art audio compression techniques exist that satisfy the requirements for this
system.
[0154] Figure 5 illustrates one particular prior art technique for
compressing video in which each individual video frame 501-503 is compressed
by compression logic 520 using a particular compression algorithm to generate
a
series of compressed frames 511-513. One embodiment of this technique is
"motion JPEG" in which each frame is compressed according to a Joint Pictures
Expert Group (JPEG) compression algorithm, based upon the discrete cosine
transform (DCT). Various different types of compression algorithms may be
employed, however, while still complying with these underlying principles
(e.g.,
wavelet-based compression algorithms such as JPEG-2000).
[0155] One problem with this type of compression is that it reduces the
data rate of each frame, but it does not exploit similarities between
successive
frames to reduce the data rate of the overall video stream. For example, as
illustrated in Figure 5, assuming a frame rate of 640x48Ox24bits/pixel =
640*480*24/8/1024=900 Kilobytes/frame (KB/frame), for a given quality of
image, motion JPEG may only compress the stream by a factor of 10, resulting
in
a data stream of 90 KB/frame. At 60 frames/sec, this would require a channel
bandwidth of 90 KB * 8 bits * 60 frames/sec = 42.2Mbps, which would be far too
high bandwidth for almost all home Internet connections in the US today, and
too
high bandwidth for many office Internet connections. Indeed, given that it
would
demand a constant data stream at such a high bandwidth, and it would be just
serving one user, even in an office LAN environment, it would consume a large
57
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
percentage of a 100Mbps Ethernet LAN's bandwidth and heavily burden Ethernet
switches supporting the LAN. Thus, the compression for motion video is
inefficient when compared with other compression techniques (such as those
described below). Moreover, single frame compression algorithms like JPEG and
JPEG-2000 that use lossy compression algorithms produce compression artifacts
that may not be noticeable in still images (e.g., an artifact within dense
foliage in
the scene may not appear as an artifact since the eye does not know exactly
how
the dense foliage should appear). But, once the scene is in motion, an
artifact can
stand out because the eye detects that the artifact changed from frame-to-
frame,
despite the fact the artifact is in an area of the scene where it might not
have been
noticeable in a still image. This results in the perception of "background
noise" in
the sequence of frames, similar in appearance to the "snow" noise visible
during
marginal analog TV reception. Of course, this type of compression may still be
used in certain embodiments described herein, but generally speaking, to avoid
background noise in the scene, a high data rate (i.e., a low compression
ratio) is
required for a given perceptual quality.
[0156] Other types of compression, such as H.264, or Windows Media
VC9, MPEG2 and MPEG4 are all more efficient at compressing a video stream
because they exploit the similarities between successive frames. These
techniques all rely upon the same general techniques to compress video. Thus,
although the H.264 standard will be described, but the same general principles
apply to various other compression algorithms. A large number of H.264
compressors and decompressor are available, including the x264 open source
software library for compressing H.264 and the FFmpeg open source software
libraries for decompressing H.264.
[0157] Figures 6a and 6b illustrate an exemplary prior art compression
technique in which a series of uncompressed video frames 501-503, 559-561 are
compressed by compression logic 620 into a series of "I frames" 611, 671; "P
frames" 612-613; and "B frames" 670. The vertical axis in Figure 6a generally
58
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
signifies the resulting size of each of the encoded frames (although the
frames are
not drawn to scale). As described above, video coding using I frames, B frames
and P frames is well understood by those of skill in the art. Briefly, an I
frame
611 is a DCT-based compression of a complete uncompressed frame 501 (similar
to a compressed JPEG image as described above). P frames 612-613 generally
are significantly smaller in size than I frames 611 because they take
advantage of
the data in the previous I frame or P frame; that is, they contain data
indicating
the changes between the previous I frame or P frame. B frames 670 are similar
to
that of P frames except that B frames use the frame in the following reference
frame as well as potentially the frame in the preceding reference frame.
[0158] For the following discussion, it will be assumed that the desired
frame rate is 60 frames/second, that each I frame is approximately 160 Kb, the
average P frame and B frame is 16 Kb and that a new I frame is generated every
second. With this set of parameters, the average data rate would be: 160 Kb +
16
Kb * 59 = 1.1Mbps. This data rate falls well within the maximum data rate for
many current broadband Internet connections to homes and offices. This
technique also tends to avoid the background noise problem from intraframe-
only
encoding because the P and B frames track differences between the frames, so
compression artifacts tend not to appear and disappear from frame-to-frame,
thereby reducing the background noise problem described above.
[0159] One problem with the foregoing types of compression is that
although the average data rate is relatively low (e.g., 1.1Mbps), a single I
frame
may take several frame times to transmit. For example, using prior art
techniques
a 2.2 Mbps network connection (e.g., DSL or cable modem with 2.2Mbps peak
of max available data rate 302 from Figure 3a) would typically be adequate to
stream video at 1.1 Mbps with a 160Kbps I frame each 60 frames. This would be
accomplished by having the decompressor queue up 1 second of video before
decompressing the video. In 1 second, 1.1Mb of data would be transmitted,
which
would be easily accommodated by a 2.2Mbps max available data rate, even
59
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
assuming that the available data rate might dip periodically by as much as
50%.
Unfortunately, this prior art approach would result in a 1-second latency for
the
video because of the 1-second video buffer at the receiver. Such a delay is
adequate for many prior art applications (e.g., the playback of linear video),
but is
far too long a latency for fast action video games which cannot tolerate more
than
70-80ms of latency.
[0160] If an attempt were made to eliminate the 1-second video buffer, it
still would not result in an adequate reduction in latency for fast action
video
games. For one, the use of B frames, as previously described, would
necessitate
the reception of all of the B frames preceding an I frame as well as the I
frame. If
we assume the 59 non-I frames are roughly split between P and B frames, then
there would be at least 29 B frames and an I frame received before any B frame
could be displayed. Thus, regardless of the available bandwidth of the
channel, it
would necessitate a delay of 29+1=30 frames of 1/60th second duration each, or
500ms of latency. Clearly that is far too long.
[01611 Thus, another approach would be to eliminate B frames and only
use I and P frames. (One consequence of this is the data rate would increase
for a
given quality level, but for the sake of consistency in this example, let's
continue
to assume that each I frame is 160Kb and the average P frame is 16Kb in size,
and thus the data rate is still 1.1Mbps) This approach eliminates the
unavoidable
latency introduced by B frames, since the decoding of each P frame is only
reliant
upon the prior received frame. A problem that remains with this approach is
that
an I frame is so much larger than an average P frame, that on a low bandwidth
channel, as is typical in most homes and in many offices, the transmission of
the I
frame adds substantial latency. This is illustrated in Figure 6b. The video
stream
data rate 624 is below the available max data rate 621 except for the I
frames,
where the peak data rate required for the I frames 623 far exceeds the
available
max data rate 622 (and even the rated max data rate 621). The data rate
required
by the P frames is less than the available max data rate. Even if the
available max
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
data rate peaks at 2.2Mbps remains steadily at its 2.2Mbps peak rate, it will
take
160Kb/2.2Mb=7lms to transmit the I frame, and if the available max data rate
622 dips by 50% (1.1Mbps), it will take 142ms to transmit the I frame. So, the
latency in transmitting the I frame will fall somewhere in between 71-142ms.
This latency is additive to the latencies identified in Figure 4b, which in
the worst
case added up to 70 ms, so this would result in a total round trip latency of
141-
222ms from the point the user actuates input device 421 until an image appears
on display device 422, which is far too high. And if the available max data
rate
dips below 2.2Mbps, the latency will increase further.
[0162] Note also that there generally are severe consequences to
"jamming" an ISP with peak data rate 623 that are far in excess of the
available
data rate 622. The equipment in different ISPs will behave differently, but
the
following behaviors are quite common among DSL and cable modem ISPs when
receiving packets at much higher data rate than the available data rate 622:
(a)
delaying the packets by queuing them (introducing latency), (b) dropping some
or
all of the packets, (c) disabling the connection for a period of time (most
likely
because the ISP is concerned it is a malicious attack, such as "denial of
service"
attack). Thus, transmitting a packet stream at full data rate with
characteristics
such as those shown in Figure 6b is not a viable option. The peaks 623 may be
queued up at the hosting service 210 and sent at a data rate below the
available
max data rate, introducing the unacceptable latency described in the preceding
paragraph.
[0163] Further, the video stream data rate sequence 624 shown in Figure
6b is a very "tame" video stream data rate sequence and would be the sort of
data
rate sequence that one would expect to result from compressing the video from
a
video sequence that does not change very much and has very little motion
(e.g.,
as would be common in video teleconferencing where the cameras are in a fixed
position and have little motion, and the objects, in the scene, e.g., seated
people
talking, show little motion).
61
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0164] The video stream data rate sequence 634 shown in Figure 6c is a
sequence typical to what one would expect to see from video with far more
action, such as might be generated in a motion picture or a video game, or in
some application software. Note that in addition to the I frame peaks 633,
there
are also P frame peaks such as 635 and 636 that are quite large and exceed the
available max data rate on many occasions. Although these P frame peaks are
not
quite as large as the I frame peaks, they still are far too large to be
carried by the
channel at full data rate, and as with the I frame peaks, they P frame peaks
must
be transmitted slowly (thereby increasingly latency).
[0165] On a high bandwidth channel (e.g., a 100Mbps LAN, or a high
bandwidth 100Mbps private connection) the network would be able to tolerate
large peaks, such as I frame peaks 633 or P frame peaks 636, and in principle,
low latency could be maintained. But, such networks are frequently shared
amongst many users (e.g., in an office environment), and such "peaky" data
would impact the performance of the LAN, particularly if the network traffic
was
routed to a private shared connection (e.g., from a remote data center to an
office). To start with, bear in mind that this example is of a relatively low
resolution video stream of 640x480 pixels at 60fps. HDTV streams of
1920x1080 at 60fps are readily handled by modern computers and displays, and
2560x1440 resolution displays at 60fps are increasingly available (e.g.,
Apple,
Inc.'s 30" display). A high action video sequence at 1920x1080 at 60fps may
require 4.5 Mbps using H.264 compression for a reasonable quality level. If we
assume the I frames peak at lOX the nominal data rate, that would result in
45Mbps peaks, as well as smaller, but still considerable, P frame peak. If
several
users were receiving video streams on the same 100Mbps network (e.g., a
private
network connection between an office and data center), it is easy to see how
the
peaks from several users' video stream could happen to align, overwhelming the
bandwidth of the network, and potentially overwhelming the bandwidth of the
backplanes of the switches supporting the users on the network. Even in the
case
62
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
of a Gigabit Ethernet network, if enough users had enough peaks aligned at
once,
it could overwhelm the network or the network switches. And, once 2560x1440
resolution video becomes more commonplace, the average video stream data rate
may be 9.5Mbps, resulting in perhaps a 95Mbps peak data rate. Needless to say,
a
100Mbps connection between a data center and an office (which today is an
exceptionally fast connection) would be completely swamped by the peak traffic
from a single user. Thus, even though LANs and private network connections
can be more tolerant of peaky streaming video, the streaming video with high
peaks is not desirable and might require special planning and accommodation by
an office's IT department.
[0166] Of course, for standard linear video applications these issues are
not a problem because the data rate is "smoothed" at the point of transmission
and the data for each frame below the max available data rate 622, and a
buffer in
the client stores a sequence of I, P and B frames before they are
decompressed.
Thus, the data rate over the network remains close to the average data rate of
the
video stream. Unfortunately, this introduces latency, even if B frames are not
used, that is unacceptable for low-latency applications such as video games
and
applications require fast response time.
[0167] One prior art solution to mitigating video streams that have high
peaks is to use a technique often referred to as "Constant Bit Rate" (CBR)
encoding. Although the term CBR would seem to imply that all frames are
compressed to have the same bit rate (i.e., size), what it usually refers to
is a
compression paradigm where a maximum bit rate across a certain number of
frames (in our case, 1 frame) is allowed. For example, in the case of Figure
6c, if
a CBR constraint were applied to the encoding that limited the bit rate to,
for
example, 70% of the rated max data rate 621, then the compression algorithm
would limit the compression of each of the frames so that any frame that would
normally be compressed using more than 70% of the rated max data rate 621
would be compressed with less bits. The result of this is that frames that
would
63
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
normally require more bits to maintain a given quality level would be
"starved"
of bits and the image quality of those frames would be worse than that of
other
frames that do not require more bits than the 70% of the rate max data rate
621.
This approach can produce acceptable results for certain types of compressed
video where there (a) little motion or scene changes are expected and (b) the
users
can accept periodic quality degradation. A good example of a CBR-suited
application is video teleconferencing since there are few peaks, and if the
quality
degrades briefly (for example, if the camera is panned, resulting in
significant
scene motion and large peaks, during the panning there may not be enough bits
for high-quality image compression, which would result in degraded image
quality), it is acceptable for most users. Unfortunately, CBR is not well-
suited
for many other applications which have scenes of high complexity or a great
deal
of motion and/or where a reasonably constant level of quality is required.
[0168] The low-latency compression logic 404 employed in one
embodiment uses several different techniques to address the range of problems
with streaming low-latency compressed video, while maintaining high quality.
First, the low-latency compression logic 404 generates only I frames and P
frames, thereby alleviating the need to wait several frame times to decode
each B
frame. In addition, as illustrated in Figure 7a, in one embodiment, the low-
latency compression logic 404 subdivides each uncompressed frame 701-760 into
a series of "tiles" and individually encodes each tile as either an I frame or
a P
frame. The group of compressed I frames and P frames are referred to herein as
"R frames" 711-770. In the specific example shown in Figure 7a, each
uncompressed frame is subdivided into a 4 x 4 matrix of 16 tiles. However,
these
underlying principles are not limited to any particular subdivision scheme.
[0169] In one embodiment, the low-latency compression logic 404
divides up the video frame into a number of tiles, and encodes (i.e.,
compresses)
one tile from each frame as an I frame (i.e., the tile is compressed as if it
is a
separate video frame of 1/16th the size of the full image, and the compression
64
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
used for this "mini" frame is I frame compression) and the remaining tiles as
P
frames (i.e., the compression used for each "mini" 1/16t frame is P frame
compression). Tiles compressed as I frames and as P frames shall be referred
to
as "I tiles" and "P tiles", respectively. With each successive video frame,
the tile
to be encoded as an I tile is changed. Thus, in a given frame time, only one
tile of
the tiles in the video frame is an I tile, and the remainder of the tiles are
P tiles.
For example, in Figure 7a, tile 0 of uncompressed frame 701 is encoded as I
tile
Io and the remaining 1-15 tiles are encoded as P tiles Pi through P15 to
produce R
frame 711. In the next uncompressed video frame 702, tile 1 of uncompressed
frame 701 is encoded as I tile Il and the remaining tiles 0 and 2 through 15
are
encoded as P tiles, Po and P2 through Pis, to produce R frame 712. Thus, the I
tiles and P tiles for tiles are progressively interleaved in time over
successive
frames. The process continues until a R tile 770 is generated with the last
tile in
the matrix encoded as an I tile (i.e., 115). The process then starts over,
generating
another R frame such as frame 711 (i.e., encoding an I tile for tile 0) etc.
Although not illustrated in Figure 7a, in one embodiment, the first R frame of
the
video sequence of R frames contains only I tiles (i.e., so that subsequent P
frames
have reference image data from which to calculate motion). Alternatively, in
one
embodiment, the startup sequence uses the same I tile pattern as normal, but
does
not include P tiles for those tiles that have not yet been encoded with an I
tile. In
other words, certain tiles are not encoded with any data until the first I
tile arrives,
thereby avoiding startup peaks in the video stream data rate 934 in Figure 9a,
which is explained in further detail below. Moreover, as described below,
various different sizes and shapes may be used for the tiles while still
complying
with these underlying principles.
[0170] The video decompression logic 412 running on the client 415
decompresses each tile as if it is a separate video sequence of small I and P
frames, and then renders each tile to the frame buffer driving display device
422.
For example, I0 and Po from R frames 711 to 770 are used to decompress and
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
render tile 0 of the video image. Similarly, Ii and Pi from R frames 711 to
770
are used to reconstruct tile 1, and so on. As mentioned above, decompression
of I
frames and P frames is well known in the art, and decompression of I tiles and
P
tiles can be accomplished by having a multiple instances of a video
decompressor
running in the client 415. Although multiplying processes would seem to
increase
the computational burden on client 415, it actually doesn't because the tile
themselves are proportionally smaller relative to the number of additional
processes, so the number of pixels displayed is the same as if there were one
process and using conventional full sized I and P frames.
[0171] This R frame technique significantly mitigates the bandwidth
peaks typically associated with I frames illustrated in Figures 6b and 6c
because
any given frame is mostly made up of P frames which are typically smaller than
I
frames. For example, assuming again that a typical I frame is 160Kb, then the
I
tiles of each of the frames illustrated in Figure 7a would be roughly 1/16 of
this
amount or 10Kb. Similarly, assuming that a typical P frame is 16 Kb, then the
P
frames for each of the tiles illustrated in Figure 7a may be roughly 1Kb The
end
result is an R frame of approximately 10Kb + 15 * 1Kb = 25Kb. So, each 60-
frame sequence would be 25Kb * 60 = 1.5Mbps. So, at 60 frames/second, this
would require a channel capable of sustaining a bandwidth of 1.5Mbps, but with
much lower peaks due to I tiles being distributed throughout the 60-frame
interval.
[0172] Note that in previous examples with the same assumed data rates
for I frames and P frames, the average data rate was 1.1Mbps. This is because
in
the previous examples, a new I frame was only introduced once every 60 frame
times, whereas in this example, the 16 tiles that make up an I frame cycle
through
in 16 frames times, and as such the equivalent of an I frame is introduced
every
16 frame times, resulting in a slightly higher average data rate. In practice,
though, introducing more frequent I frames does not increase the data rate
linearly. This is due to the fact that a P frame (or a P tile) primarily
encodes the
66
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
difference from the prior frame to the next. So, if the prior frame is quite
similar
to the next frame, the P frame will be very small, if the prior frame is quite
different from the next frame, the P frame will be very large. But because a P
frame is largely derived from the previous frame, rather than from the actual
frame, the resulting encoded frame may contain more errors (e.g., visual
artifacts)
than an I frame with an adequate number of bits. And, when one P frame follows
another P frame, what can occur is an accumulation of errors that gets worse
when there is a long sequence of P frames. Now, a sophisticated video
compressor will detect the fact that the quality of the image is degrading
after a
sequence of P frames and, if necessary, it will allocate more bits to
subsequent P
frames to bring up the quality or, if it is the most efficient course of
action,
replace a P frame with an I frame. So, when long sequences of P frames are
used
(e.g., 59 P frames, as in prior examples above) particularly when the scene
has a
great deal of complexity and/or motion, typically, more bits are needed for P
frames as they get further removed from an I frame.
[0173] Or, to look at P frames from the opposite point of view, P frames
that closely follow an I frame tend to require less bits than P frames that
are
further removed from an I frame. So, in the example shown in Figure 7a, no P
frame is further than 15 frames removed from an I frame that precedes it,
where
as in the prior example, a P frame could be 59 frames removed from an I frame.
Thus, with more frequent I frames, the P frames are smaller. Of course, the
exact
relative sizes will vary based on the nature of the video stream, but in the
example
of Figure 7a, if an I tile is 10Kb, P tiles on average, may be only 0.75kb in
size
resulting in 10Kb + 15 * 0.75Kb = 21.25Kb, or at 60 frames per second, the
data
rate would be 21.25Kb * 60 = 1.3Mbps, or about 16% higher data rate than a
stream with an I frame followed by 59 P frames at 1.1Mbps. Once, again, the
relative results between these two approaches to video compression will vary
depending up on the video sequence, but typically, we have found empirically
that using R-frames require about 20% more bits for a given level of quality
than
67
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
using I /P frame sequences. But, of course, R frames dramatically reduce the
peaks which make the video sequences usable with far less latency than I/P
frame
sequences.
[0174] R frames can be configured in a variety of different ways,
depending upon the nature of the video sequence, the reliability of the
channel,
and the available data rate. In an alternative embodiment, a different number
of
tiles is used than 16 in a 4x4 configuration. For example 2 tiles may be used
in a
2x1 or 1x2 configuration, 4 tiles may be used in a 2x2, 4x1 or 1x4
configuration,
6 tiles may be used in a 3x2, 2x3, 6x1 or 1x6 configurations or 8 tiles may be
used in a 4x2 (as shown in Figure 7b), 2x4, 8x1 or 1x8 configuration. Note
that
the tiles need not be square, nor must the video frame be square, or even
rectangular. The tiles can be broken up into whatever shape best suits the
video
stream and the application used.
[0175] In another embodiment, the cycling of the I and P tiles is not
locked to the number of tiles. For example, in an 8-tile 4x2 configuration, a
16-
cycle sequence can still be used as illustrated in Figure 7b. Sequential
uncompressed frames 721, 722, 723 are each divided into 8 tiles, 0-7 and each
tile
is compressed individually. From R frame 731, only tile 0 is compressed as an
I
tile, and the remaining tiles are compressed as P tiles. For subsequent R
frame
732 all of the 8 tiles are compressed as P tiles, and then for subsequent R
frame
733, tile 1 is compressed as an I tile and the other tiles are all compressed
as P
tiles. And, so the sequencing continues for 16 frames, with an I tile
generated
only every other frame, so the last I tile is generated for tile 7 during the
15th
frame time (not shown in Figure 7b) and during the 16`h frame time R frame 780
is compressed using all P tiles. Then, the sequence begins again with tile 0
compressed as an I tile and the other tiles compressed as P tiles. As in the
prior
embodiment, the very first frame of the entire video sequence would typically
be
all I tiles, to provide a reference for P tiles from that point forward. The
cycling
of I tiles and P tiles need not even be an even multiple of the number of
tiles. For
68
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
example, with 8 tiles, each frame with an I tile can be followed by 2 frames
with
all P tiles, before another I tile is used. In yet another embodiment, certain
tiles
may be sequenced with I tiles more often than other tiles if, for example,
certain
areas of the screen are known to have more motion requiring from frequent I
tiles,
while others are more static (e.g., showing a score for a game) requiring less
frequent I tiles. Moreover, although each frame is illustrated in Figures 7a-b
with
a single I tile, multiple I tiles may be encoded in a single frame (depending
on the
bandwidth of the transmission channel). Conversely, certain frames or frame
sequences may be transmitted with no I tiles (i.e., only P tiles).
[0176] The reason the approaches of the preceding paragraph works well
is that while not having I tiles distributed across every single frame would
seem
to be result in larger peaks, the behavior of the system is not that simple.
Since
each tile is compressed separately from the other tiles, as the tiles get
smaller the
encoding of each tile can become less efficient, because the compressor of a
given tile is not able to exploit similar image features and similar motion
from the
other tiles. Thus, dividing up the screen into 16 tiles generally will result
in a less
efficient encoding than dividing up the screen into 8 tiles. But, if the
screen is
divided into 8 tiles and it causes the data of a full I frame to be introduced
every 8
frames instead of every 16 frames, it results in a much higher data rate
overall.
So, by introducing a full I frame every 16 frames instead of every 8 frames,
the
overall data rate is reduced. Also, by using 8 larger tiles instead of 16
smaller
tiles, the overall data rate is reduced, which also mitigates to some degree
the data
peaks caused by the larger tiles.
[0177] In another embodiment, the low-latency video compression logic
404 in Figures 7a and 7b controls the allocation of bits to the various tiles
in the R
frames either by being pre-configured by settings, based on known
characteristics
of the video sequence to be compressed, or automatically, based upon an
ongoing
analysis of the image quality in each tile. For example, in some racing video
games, the front of the player's car (which is relatively motionless in the
scene)
69
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
takes up a large part of the lower half of the screen, whereas the upper half
of the
screen is entirely filled with the oncoming roadway, buildings and scenery,
which
is almost always in motion. If the compression logic 404 allocates an equal
number of bits to each tile, then the tiles on the bottom half of the screen
(tiles 4-
7) in uncompressed frame 721 in Figure 7b, will generally be compressed with
higher quality than tiles than the tiles in the upper half of the screen
(tiles 0-3) in
uncompressed frame 721 in Figure 7b. If this particular game, or this
particular
scene of the game is known to have such characteristics, then the operators of
the
hosting service 210 can configure the compression logic 404 to allocate more
bits
to the tiles in the top of the screen than to tiles at the bottom of the
screen. Or, the
compression logic 404 can evaluate the quality of the compression of the tiles
after frames are compressed (using one or more of many compression quality
metrics, such as Peak Signal-To-Noise Ratio (PSNR)) and if it determines that
over a certain window of time, certain tiles are consistently producing better
quality results, then it gradually allocates more bits to tiles that are
producing
lower quality results, until the various tiles reach a similar level of
quality. In an
alternative embodiment, the compressor logic 404 allocates bits to achieve
higher
quality in a particular tile or group of tiles. For example, it may provide a
better
overall perceptual appearance to have higher quality in the center of the
screen
than at the edges.
[0178] In one embodiment, to improve resolution of certain regions of the
video stream, the video compression logic 404 uses smaller tiles to encode
areas
of the video stream with relatively more scene complexity and/or motion than
areas of the video stream with relatively less scene complexity and/or motion.
For example, as illustrated in Figure 8, smaller tiles are employed around a
moving character 805 in one area of one R frame 811 (potentially followed by a
series of R frames with the same tile sizes (not shown)). Then, when the
character 805 moves to a new area of the image, smaller tiles are used around
this
new area within another R frame 812, as illustrated. As mentioned above,
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
various different sizes and shapes may be employed as "tiles" while still
complying with these underlying principles.
[0179] While the cyclic UP tiles described above substantially reduce the
peaks in the data rate of a video stream, they do not eliminate the peaks
entirely,
particularly in the case of rapidly-changing or highly complex video imagery,
such as occurs with motion pictures, video games, and some application
software.
For example, during a sudden scene transition, a complex frame may be followed
by another complex frame that is completely different. Even though several I
tiles
may have preceded the scene transition by only a few frame times, they don't
help in this situation because the new frame's material has no relation to the
previous I tiles. In such a situation (and in other situations where even
though not
everything changes, much of the image changes), the video compressor 404 will
determine that many, if not all, of the P tiles are more efficiently coded as
I tiles,
and what results is a very large peak in the data rate for that frame.
[0180] As discussed previously, it is simply the case that with most
consumer-grade Internet connections (and many office connections), it simply
is
not feasible to "jam" data that exceeds the available maximum data rate shown
as
622 in Figure 6c, along with the rated maximum data rate 621. Note that the
rated maximum data rate 621 (e.g., "6Mbps DSL") is essentially a marketing
number for users considering the purchase of an Internet connection, but
generally it does not guarantee a level of performance. For the purposes of
this
application, it is irrelevant, since our only concern is the available maximum
data
rate 622 at the time the video is streamed through the connection.
Consequently,
in Figures 9a and 9c, as we describe a solution to the peaking problem, the
rated
maximum data rate is omitted from the graph, and only the available maximum
data rate 922 is shown. The video stream data rate must not exceed the
available
maximum data rate 922.
[01811 To address this, the first thing that the video compressor 404 does
is determine a peak data rate 941, which is a data rate the channel is able to
71
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
handle steadily. This rate can be determined by a number of techniques. One
such
technique is by gradually sending an increasingly higher data rate test stream
from the hosting service 210 to the client 415 in Figures 4a and 4b, and
having
the client provide feedback to the hosting service as to the level of packet
loss and
latency. As the packet loss and/or latency begins to show a sharp increase,
that is
an indication that the available maximum data rate 922 is being reached. After
that, the hosting service 210 can gradually reduce the data rate of the test
stream
until the client 415 reports that for a reasonable period of time the test
stream has
been received with an acceptable level of packet loss and the latency is near
minimal. This establishes a peak maximum data rate 941, which will then be
used
as a peak data rate for streaming video. Over time, the peak data rate 941
will
fluctuate (e.g., if another user in a household starts to heavily use the
Internet
connection), and the client 415 will need to constantly monitor it to see
whether
packet loss or latency increases, indicating the available max data rate 922
is
dropping below the previously established peak data rate 941, and if so the
peak
data rate 941. Similarly, if over time the client 415 finds that the packet
loss and
latency remain at optimal levels, it can request that the video compressor
slowly
increases the data rate to see whether the available maximum data rate has
increased (e.g., if another user in a household has stopped heavy use of the
Internet connection), and again waiting until packet loss and/or higher
latency
indicates that the available maximum data rate 922 has been exceeded, and
again
a lower level can be found for the peak data rate 941, but one that is perhaps
higher than the level before testing an increased data rate. So, by using this
technique (and other techniques like it) a peak data rate 941 can be found,
and
adjusted periodically as needed. The peak data rate 941 establishes the
maximum
data rate that can be used by the video compressor 404 to stream video to the
user. The logic for determining the peak data rate may be implemented at the
user premises 211 and/or on the hosting service 210. At the user premises 211,
the client device 415 performs the calculations to determine the peak data
rate
72
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
and transmits this information back to the hosting service 210; at the hosting
service 210, a server 402 at the hosting service performs the calculations to
determine the peak data rate based on statistics received from the client 415
(e.g.,
packet loss, latency, max data rate, etc).
[0182] Figure 9a shows an example video stream data rate 934 that has
substantial scene complexity and/or motion that has been generated using the
cyclic I/P tile compression techniques described previously and illustrated in
Figures 7a, 7b and 8. The video compressor 404 has been configured to output
compressed video at an average data rate that is below the peak data rate 941,
and
note that, most of the time, the video stream data rate remains below the peak
data rate 941. A comparison of data rate 934 with video stream data rate 634
shown in Figure 6c created using I/P/B or I/P frames shows that the cyclic I/P
tile
compression produces a much smoother data rate. Still, at frame 2x peak 952
(which approaches 2x the peak data rate 942) and frame 4x peak 954 (which
approaches 4x the peak data rate 944), the data rate exceeds the peak data
rate
941, which is unacceptable. In practice, even with high action video from
rapidly
changing video games, peaks in excess of peak data rate 941 occur in less than
2% of frames, peaks in excess of 2x peak data rate 942 occur rarely, and peaks
in
excess of 3x peak data rate 943 occur hardly ever. But, when they do occur
(e.g.,
during a scene transition), the data rate required by them is necessary to
produce a
good quality video image.
[0183] One way to solve this problem is simply to configure the video
compressor 404 such that its maximum data rate output is the peak data rate
941.
Unfortunately, the resulting video output quality during the peak frames is
poor
since the compression algorithm is "starved" for bits. What results is the
appearance of compression artifacts when there are sudden transitions or fast
motion, and in time, the user comes to realize that the artifacts always crop
up
when there is sudden changes or rapid motion, and they can become quite
annoying.
73
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0184] Although the human visual system is quite sensitive to visual
artifacts that appear during sudden changes or rapid motion, it is not very
sensitive to detecting a reduction in frame rate in such situations. In fact,
when
such sudden changes occur, it appears that the human visual system is
preoccupied with tracking the changes, and it doesn't notice if the frame rate
briefly drops from 60fps to 30fps, and then returns immediately to 60fps. And,
in
the case of a very dramatic transition, like a sudden scene change, the human
visual system doesn't notice if the frame rate drops to 20fps or even l5fps,
and
then immediately returns to 60fps. So long as the frame rate reduction only
occurs infrequently, to a human observer, it appears that the video has been
continuously running at 60fps.
[0185] This property of the human visual system is exploited by the
techniques illustrated in Figure 9b. A server 402 (from Figures 4a and 4b)
produces an uncompressed video output stream at a steady frame rate (at 60fps
in
one embodiment). A timeline shows each frame 961-970 output each 1/60th
second. Each uncompressed video frame, starting with frame 961, is output to
the low-latency video compressor 404, which compresses the frame in less than
a
frame time, producing for the first frame compressed frame 19 8 1. The data
produced for the compressed frame 1 981 may be larger or smaller, depending
upon many factors, as previously described. If the data is small enough that
it can
be transmitted to the client 415 in a frame time (1/60th second) or less at
the peak
data rate 941, then it is transmitted during transmit time (xmit time) 991
(the
length of the arrow indicates the duration of the transmit time). In the next
frame
time, server 402 produces uncompressed frame 2 962, it is compressed to
compressed frame 2 982, and it is transmitted to client 415 during transmit
time
992, which is less than a frame time at peak data rate 941.
[0186] Then, in the next frame time, server 402 produces uncompressed
frame 3 963. When it is compressed by video compressor 404, the resulting
compressed frame 3 983 is more data than can be transmitted at the peak data
rate
74
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
941 in one frame time. So, it is transmitted during transmit time (2x peak)
993,
which takes up all of the frame time and part of the next frame time. Now,
during
the next frame time, server 402 produces another uncompressed frame 4 964 and
outputs it to video compressor 404 but the data is ignored and illustrated
with
974. This is because video compressor 404 is configured to ignore further
uncompressed video frames that arrive while it is still transmitting a prior
compressed frame. Of course client 415's video decompressor will fail to
receive
frame 4, but it simply continues to display on display device 422 frame 3 for
2
frame times (i.e., briefly reduces the frame rate from 60fps to 30fps).
[0187] For the next frame 5, server 402 outputs uncompressed frame 5
965, is compressed to compressed frame 5 985 and transmitted within 1 frame
during transmit time 995. Client 415's video decompressor decompresses frame 5
and displays it on display device 422. Next, server 402 outputs uncompressed
frame 6 966, video compressor 404 compresses it to compressed frame 6 986, but
this time the resulting data is very large. The compressed frame is
transmitted
during transmit time (4x peak) 996 at the peak data rate 941, but it takes
almost 4
frame times to transmit the frame. During the next 3 frame times, video
compressor 404 ignores 3 frames from server 402, and client 415's decompressor
holds frame 6 steadily on the display device 422 for 4 frames times (i.e.,
briefly
reduces the frame rate from 60fps to 15fps). Then finally, server 402 outputs
frame 10 970, video compressor 404 compresses it into compressed frame 10
987, and it is transmitted during transmit time 997, and client 415's
decompressor
decompresses frame 10 and displays it on display device 422 and once again the
video resumes at 60fps.
[0188] Note that although video compressor 404 drops video frames from
the video stream generated by server 402, it does not drop audio data,
regardless
of what form the audio comes in, and it continues to compress the audio data
when video frames are dropped and transmit them to client 415, which continues
to decompress the audio data and provide the audio to whatever device is used
by
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
the user to playback the audio. Thus audio continues unabated during periods
when frames are dropped. Compressed audio consumes a relatively small
percentage of bandwidth, compared to compressed video, and as result does not
have a major impact on the overall data rate. Although it is not illustrated
in any
of the data rate diagrams, there is always data rate capacity reserved for the
compressed audio stream within the peak data rate 941.
[0189] The example just described in Figure 9b was chosen to illustrate
how the frame rate drops during data rate peaks, but what it does not
illustrate is
that when the cyclic UP tile techniques described previously are used, such
data
rate peaks, and the consequential dropped frames are rare, even during high
scene
complexity/high action sequences such as those that occur in video games,
motion pictures and some application software. Consequently, the reduced frame
rates are infrequent and brief, and the human visual system does not detect
them.
[0190] If the frame rate reduction mechanism just described is applied to
the video stream data rate illustrated in Figure 9a, the resulting video
stream data
rate is illustrated in Figure 9c. In this example, 2x peak 952 has been
reduced to
flattened 2x peak 953, and 4x peak 955 has been reduced to flattened 4x peak
955, and the entire video stream data rate 934 remains at or below the peak
data
rate 941.
[0191 ] Thus, using the techniques described above, a high action video
stream can be transmitted with low latency through the general Internet and
through a consumer-grade Internet connection. Further, in an office
environment
on a LAN (e.g., 100Mbs Ethernet or 802.11g wireless) or on a private network
(e.g., 100Mbps connection between a data center an offices) a high action
video
stream can be transmitted without peaks so that multiple users (e.g.,
transmitting
1920x1080 at 60fps at 4.5Mbps) can use the LAN or shared private data
connection without having overlapping peaks overwhelming the network or the
network switch backplanes.
76
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0192] DATA RATE ADJUSTMENT
[0193] In one embodiment, the hosting service 210 initially assesses the
available maximum data rate 622 and latency of the channel to determine an
appropriate data rate for the video stream and then dynamically adjusts the
data
rate in response. To adjust the data rate, the hosting service 210 may, for
example, modify the image resolution and/or the number of frames/second of the
video stream to be sent to the client 415. Also, the hosting service can
adjust the
quality level of the compressed video. When changing the resolution of the
video
stream, e.g., from a 1280 x 720 resolution to a 640 x 360 the video
decompression logic 412 on the client 415 can scale up the image to maintain
the
same image size on the display screen.
[0194] In one embodiment, in a situation where the channel completely
drops out, the hosting service 210 pauses the game. In the case of a
multiplayer
game, the hosting service reports to the other users that the user has dropped
out
of the game and/or pauses the game for the other users.
[0195] DROPPED OR DELAYED PACKETS
[0196] In one embodiment, if data is lost due to packet loss between the
video compressor 404 and client 415 in Figures 4a or 4b, or due to a packet
being
received out of order that arrives too late to decompress and meet the latency
requirements of the decompressed frame, the video decompression logic 412 is
able to mitigate the visual artifacts. In a streaming UP frame implementation,
if
there is a lost/delayed packet, the entire screen is impacted, potentially
causing
the screen to completely freeze for a period of time or show other screen-wide
visual artifacts. For example, if a lost/delayed packet causes the loss of an
I
frame, then the decompressor will lack a reference for all of the P frames
that
follow until a new I frame is received. If a P frame is lost, then it will
impact the
P frames for the entire screen that follow. Depending on how long it will be
before an I frame appears, this will have a longer or shorter visual impact.
Using
interleaved UP tiles as shown in Figures 7a and 7b, a lost/delayed packet is
much
77
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
less likely to impact the entire screen since it will only affect the tiles
contained in
the affected packet. If each tile's data is sent within an individual packet,
then if a
packet is lost, it will only affect one tile. Of course, the duration of the
visual
artifact will depend on whether an I tile packet is lost and, if a P tile is
lost, how
many frames it will take until an I tile appears. But, given that different
tiles on
the screen are being updated with I frames very frequently (potentially every
frame), even if one tile on the screen is affected, other tiles may not be.
Further, if
some event cause a loss of several packets at once (e.g., spike in power next
to a
DSL line that briefly disrupts the data flow), then some of the tiles will be
affected more than others, but because some tiles will quickly be renewed with
a
new I tile, they will be only briefly affected. Also, with a streaming I/P
frame
implementation, not only are the I frames the most critical frame, but the I
frames
are extremely large, so if there is an event that causes a dropped/delayed
packet,
there is a higher probability that an I frame will be affected (i.e., if any
part of an
I frame is lost, it is unlikely that the I frame can be decompressed at all)
than a
much smaller I tile. For all of these reasons, using I/P tiles results in far
fewer
visual artifacts when packets are dropped/delayed than with I/P frames.
[0197] One embodiment attempts to reduce the effect of lost packets by
intelligently packaging the compressed tiles within the TCP (transmission
control
protocol) packets or UDP (user datagram protocol) packets. For example, in one
embodiment, tiles are aligned with packet boundaries whenever possible. Figure
10a illustrates how tiles might be packed within a series of packets 1001-1005
without implementing this feature. Specifically, in Figure 10a, tiles cross
packet
boundaries and are packed inefficiently so that the loss of a single packet
results
in the loss of multiple frames. For example, if packets 1003 or 1004 are lost,
three tiles are lost, resulting in visual artifacts.
[0198] By contrast, Figure 10b illustrates tile packing logic 1010 for
intelligently packing tiles within packets to reduce the effect of packet
loss. First,
the tile packing logic 1010 aligns tiles with packet boundaries. Thus, tiles
Ti,
78
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
T3, T4, T7, and T2 are aligned with the boundaries of packets 1001-1005,
respectively. The tile packing logic also attempts to fit tiles within packets
in the
most efficient manner possible, without crossing packet boundaries. Based on
the
size of each of the tiles, tiles Ti and T6 are combined in one packet 1001; T3
and
T5 are combined in one packet 1002; tiles T4 and T8 are combined in one packet
1003; tile T8 is added to packet 1004; and tile T2 is added to packet 1005.
Thus,
under this scheme, a single packet loss will result in the loss of no more
than 2
tiles (rather than 3 tiles as illustrated in Figure 10a).
[0199] One additional benefit to the embodiment shown in Figure 10b is
that the tiles are transmitted in a different order in which they are
displayed
within the image. This way, if adjacent packets are lost from the same event
interfering with the transmission it will affect areas which are not near each
other
on the screen, creating a less noticeable artifacting on the display.
[0200] One embodiment employs forward error correction (FEC)
techniques to protect certain portions of the video stream from channel
errors. As
is known in the art, FEC techniques such as Reed-Solomon and Viterbi generate
and append error correction data information to data transmitted over a
communications channel. If an error occurs in the underlying data (e.g., an I
frame), then the FEC may be used to correct the error.
[0201] FEC codes increase the data rate of the transmission, so ideally,
they are only used where they are most needed. If data is being sent that
would
not result in a very noticeable visual artifact, it may be preferable to not
use FEC
codes to protect the data. For example, a P tile that immediately precedes an
I tile
that is lost will only create a visual artifact (i.e., on tile on the screen
will not be
updated) for 1/60`h of second on the screen. Such a visual artifact is barely
detectable by the human eye. As P tiles are further back from an I tile,
losing a P
tile becomes increasingly more noticeable. For example, if a tile cycle
pattern is
an I tile followed by 15 P tiles before an I tile is available again, then if
the P tile
immediately following an I tile is lost, it will result in that tile showing
an
79
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
incorrect image for 15 frame times (at 60 fps, that would be 250ms). The human
eye will readily detect a disruption in a stream for 250ms. So, the further
back a P
tile is from a new I tile (i.e., the closer a P tiles follows an I tile), the
more
noticeable the artifact. As previously discussed, though, in general, the
closer a P
tile follows an I tile, the smaller the data for that P tile. Thus, P tiles
following I
tiles not only are more critical to protect from being lost, but they are
smaller in
size. And, in general, the smaller the data is that needs to be protected, the
smaller
the FEC code needs to be to protect it.
[0202] So, as illustrated in Figure l la, in one embodiment, because of the
importance of I tiles in the video stream, only I tiles are provided with FEC
codes. Thus, FEC 1101 contains error correction code for I tile 1100 and FEC
1104 contains error correction code for I tile 1103. In this embodiment, no
FEC
is generated for the P tiles.
[0203] In one embodiment illustrated in Figure l lb FEC codes are also
generated for P tiles which are most likely to cause visual artifacts if lost.
In this
embodiment, FECs 1105 provide error correction codes for the first 3 P tiles,
but
not for the P tiles that follow. In another embodiment, FEC codes are
generated
for P tiles which are smallest in data size (which will tend to self-select P
tiles
occurring the soonest after an I tile, which are the most critical to
protect).
[0204] In another embodiment, rather than sending an FEC code with a
tile, the tile is transmitted twice, each time in a different packet. If one
packet is
lost/delayed, the other packet is used.
[0205] In one embodiment, shown in Figure l lc, FEC codes 1111 and
1113 are generated for audio packets, 1110 and 1112, respectively, transmitted
from the hosting service concurrently with the video. It is particularly
important
to maintain the integrity of the audio in a video stream because distorted
audio
(e.g., clicking or hissing) will result in a particularly undesirable user
experience.
The FEC codes help to ensure that the audio content is rendered at the client
computer 415 without distortion.
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0206] In another embodiment, rather than sending an FEC code with
audio data, the audio data is transmitted twice, each time in a different
packet. If
one packet is lost/delayed, the other packet is used.
[0207] In addition, in one embodiment illustrated in Figure I Id, FEC
codes 1121 and 1123 are used for user input commands 1120 and 1122,
respectively (e.g., button presses) transmitted upstream from the client 415
to the
hosting service 210. This is important because missing a button press or a
mouse
movement in a video game or an application could result in an undesirable user
experience.
[0208] In another embodiment, rather than sending an FEC code with user
input command data, the user input command data is transmitted twice, each
time
in a different packet. If one packet is lost/delayed, the other packet is
used.
[0209] In one embodiment, the hosting service 210 assesses the quality of
the communication channel with the client 415 to determine whether to use FEC
and, if so, what portions of the video, audio and user commands to which FEC
should be applied. Assessing the "quality" of the channel may include
functions
such as evaluating packet loss, latency, etc, as described above. If the
channel is
particularly unreliable, then the hosting service 210 may apply FEC to all of
I
tiles, P tiles, audio and user commands. By contrast, if the channel is
reliable,
then the hosting service 210 may apply FEC only to audio and user commands, or
may not apply FEC to audio or video, or may not use FEC at all. Various other
permutations of the application of FEC may be employed while still complying
with these underlying principles. In one embodiment, the hosting service 210
continually monitors the conditions of the channel and changes the FEC policy
accordingly.
[0210] In another embodiment, referring to Figures 4a and 4b, when a
packet is lost/delayed resulting in the loss of tile data or if, perhaps
because of a
particularly bad packet loss, the FEC is unable to correct lost tile data, the
client
415 assesses how many frames are left before a new I tile will be received and
81
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
compares it to the round-trip latency from the client 415 to hosting service
210. If
the round-trip latency is less than the number of frames before a new I tile
is due
to arrive, then the client 415 sends a message to the hosting service 210
requesting a new I tile. This message is routed to the video compressor 404,
and
rather than generating a P tile for the tile whose data had been lost, it
generates an
I tile. Given that the system shown in Figs. 4a and 4b is designed to provide
a
round-trip latency that is typically less than 80ms, this results in a tile
being
corrected within 80ms (at 60fps, frames are 16.67ms of duration, thus in full
frame times, 80ms latency would result in a corrected a tile within 83.33ms,
which is 5 frame times-a noticeable disruption, but far less noticeable than,
for
example, a 250ms disruption for 15 frames). When the compressor 404 generates
such an I tile out of its usual cyclic order, if the I tile would cause the
bandwidth
of that frame to exceed the available bandwidth, then the compressor 404 will
delay the cycles of the other tiles so that the other tiles receive P tiles
during that
frame time (even if one tile would normally be due an I tile during that
frame),
and then starting with the next frame the usual cycling will continue, and the
tile
that normally would have received an I tile in the preceding frame will
receive an
I tile. Although this action briefly delays the phase of the R frame cycling,
it
normally will not be noticeable visually.
[0211] VIDEO AND AUDIO COMPRESSOR/DECOMPRESSOR
IMPLEMENTATION
[0212] Figure 12 illustrates one particular embodiment in which a multi-
core and/or multi-processor 1200 is used to compress 8 tiles in parallel. In
one
embodiment, a dual processor, quad core Xeon CPU computer system running at
2.66 GHz or higher is used, with each core implementing the open source x264
H.264 compressor as an independent process. However, various other
hardware/software configurations may be used while still complying with these
underlying principles. For example, each of the CPU cores can be replaced with
an H.264 compressor implemented in an FPGA. In the example shown in Figure
82
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
12, cores 1201-1208 are used to concurrently process the I tiles and P tiles
as
eight independent threads. As is well known in the art, current multi-core and
multi-processor computer systems are inherently capable of multi-threading
when
integrated with multi-threading operating systems such as Microsoft Windows
XP Professional Edition (either 64-bit or the 32-bit edition) and Linux.
[0213] In the embodiment illustrated in Figure 12, since each of the 8
cores is responsible for just one tile, it operates largely independently from
the
other cores, each running a separate instantiation of x264. A PCI Express xl-
based DVI capture card, such as the Sendero Video Imaging IP Development
Board from Microtronix of Oosterhout, The Netherlands is used to capture
uncompressed video at 640x480, 800x600, or 1280x720 resolution, and the
FPGA on the card uses Direct Memory Access (DMA) to transfer the captured
video through the DVI bus into system RAM. The tiles are arranged in a 4x2
arrangement 1205 (although they are illustrated as square tiles, in this
embodiment they are of 160x240 resolution). Each instantiation of x264's is
configured to compress one of the 8 160x240 tiles, and they are synchronized
such that, after an initial I tile compression, each core enters into a cycle,
each
one frame out of phase with the other, to compress one I tile followed by
seven P
tiles, and illustrated in Figure 12.
[0214] Each frame time, the resulting compressed tiles are combined into
a packet stream, using the techniques previously described, and then the
compressed tiles are transmitted to a destination client 415.
[0215] Although not illustrated in Figure 12, if the data rate of the
combined 8 tiles exceeds a specified peak data rate 941, then all 8 x264
processes
are suspended for as many frame times as are necessary until the data for the
combined 8 tiles has been transmitted.
[0216] In one embodiment, client 415 is implemented as software on a PC
running 8 instantiations of FFmpeg. A receiving process receives the 8 tiles,
and
83
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
each tile is routed to an FFmpeg instantiation, which decompresses the tile
and
renders it to an appropriate tile location on the display device 422.
[0217] The client 415 receives keyboard, mouse, or game controller input
from the PC's input device drivers and transmits it to the server 402. The
server
402 then applies the received input device data and applies it to the game or
application running on the server 402, which is a PC running Windows using an
Intel 2.16GHz Core Duo CPU. The server 402 then produces a new frame and
outputs it through its DVI output, either from a motherboard-based graphics
system, or through a NVIDIA 8800GTX PCI Express card's DVI output.
[0218] Simultaneously, the server 402 outputs the audio produced by
game or applications through its digital audio output (e.g., S/PDIF), which is
coupled to the digital audio input on the dual quad-core Xeon-based PC that is
implementing the video compression. A Vorbis open source audio compressor is
used to compress the audio simultaneously with the video using whatever core
is
available for the process thread. In one embodiment, the core that completes
compressing its tile first executes the audio compression. The compressed
audio
is then transmitted along with the compressed video, and is decompressed on
the
client 415 using a Vorbis audio decompressor.
[0219] HOSTING SERVICE SERVER CENTER DISTRIBUTION
[0220] Light through glass, such as optical fiber, travels at some fraction
of the speed of light in a vacuum, and so an exact propagation speed for light
in
optical fiber could be determined. But, in practice, allowing time for routing
delays, transmission inefficiencies, and other overhead, we have observed that
optimal latencies on the Internet reflect transmission speeds closer to 50%
the
speed of light. Thus, an optimal 1000 mile round trip latency is approximately
22ms, and an optimal 3000 mile round trip latency is about 64ms. Thus, a
single
server on one US coast will be too far away to serve clients on the other
coast
(which can be as far as 3000 miles away) with the desired latency. However, as
illustrated in Figure 13a, if the hosting service 210 server center 1300 is
located
84
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
in the center of the US (e.g., Kansas, Nebraska, etc.), such that the distance
to any
point in the continental US is approximately 1500 miles or less, the round
trip
Internet latency could be as low as 32 ms. Referring to Figure 4b, note that
although the worst-case latencies allowed for the user ISP 453 is 25ms,
typically,
we have observed latencies closer to 10-15ms with DSL and cable modem
systems. Also, Figure 4b assumes a maximum distance from the user premises
211 to the hosting center 210 of 1000 miles. Thus, with a typical user ISP
round
trip latency of 15ms used and a maximum Internet distance of 1500 miles for a
round trip latency of 32ms, the total round trip latency from the point a user
actuates input device 421 and sees a response on display device 422 is
1+1+15+32+1+16+6+8 = 80ms. So, the 80ms response time can be typically
achieved over an Internet distance of 1500 miles. This would allow any user
premises with a short enough user ISP latency 453 in the continental US to
access
a single server center that is centrally located.
[0221] In another embodiment, illustrated in Figure 13b, the hosting
service 210 server centers, HS 1-HS6, are strategically positioned around the
United States (or other geographical region), with certain larger hosting
service
server centers positioned close to high population centers (e.g., HS2 and
HS5). In
one embodiment, the server centers HS1-HS6 exchange information via a
network 1301 which may be the Internet or a private network or a combination
of
both. With multiple server centers, services can be provided at lower latency
to
users that have high user ISP latency 453.
[0222] Although distance on the Internet is certainly a factor that
contributes to round trip latency through the Internet, sometimes other
factors
come into play that are largely unrelated to latency. Sometimes a packet
stream is
routed through the Internet to a far away location and back again, resulting
in
latency from the long loop. Sometimes there is routing equipment on the path
that
is not operating properly, resulting in a delay of the transmission. Sometimes
there is a traffic overloading a path which introduces delay. And, sometimes,
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
there is a failure that prevents the user's ISP from routing to a given
destination at
all. Thus, while the general Internet usually provides connections from one
point
to another with a fairly reliable and optimal route and latency that is
largely
determined by distance (especially with long distance connections that result
in
routing outside of the user's local area) such reliability and latency is by
no
means guaranteed and often cannot be achieved from a user's premises to a
given
destination on the general Internet.
[0223] In one embodiment, when a user client 415 initially connects to
the hosting service 210 to play a video game or use an application, the client
communicates with each of the hosting service server centers HS1-HS6 available
upon startup (e.g., using the techniques described above). If the latency is
low
enough for a particular connection, then that connection is used. In one
embodiment, the client communicates with all, or a subset, of the hosting
service
server centers the one with the lowest latency connection is selected. The
client
may select the service center with the lowest latency connection or the
service
centers may identify the one with the lowest latency connection and provide
this
information (e.g., in the form of an Internet address) to the client.
[0224] If a particular hosting service server center is overloaded and/or
the user's game or application can tolerate the latency to another, less
loaded
hosting service server center, then the client 415 may be redirected to the
other
hosting service server center. In such a situation, the game or application
the user
is running would be paused on the server 402 at the user's overloaded server
center, and the game or application state data would be transferred to a
server 402
at another hosting service server center. The game or application would then
be
resumed. In one embodiment, the hosting service 210 would wait until the game
or application has either reached a natural pausing point (e.g., between
levels in a
game, or after the user initiates a "save" operation in application) to do the
transfer. In yet another embodiment, the hosting service 210 would wait until
user
86
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
activity ceases for a specified period of time (e.g., 1 minute) and then would
initiate the transfer at that time.
[0225] As described above, in one embodiment, the hosting service 210
subscribes to an Internet bypass service 440 of Figure 14 to attempt to
provide
guaranteed latency to its clients. Internet bypass services, as used herein,
are
services that provide private network routes from one point to another on the
Internet with guaranteed characteristics (e.g., latency, data rate, etc.). For
example, if the hosting service 210 was receiving large amount of traffic from
users using AT&T's DSL service offering in San Francisco, rather than routing
to
AT&T's San Francisco-based central offices, the hosting service 210 could
lease
a high-capacity private data connection from a service provider (perhaps AT&T
itself or another provider) between the San Francisco-based central offices
and
one or more of the server centers for hosting service 210. Then, if routes
from all
hosting service server centers HS1-HS6 through the general Internet to a user
in
San Francisco using AT&T DSL result in too high latency, then private data
connection could be used instead. Although private data connections are
generally more expensive than the routes through the general Internet, so long
as
they remain a small percentage of the hosting service 210 connections to
users,
the overall cost impact will be low, and users will experience a more
consistent
service experience.
[0226] Server centers often have two layers of backup power in the event
of power failure. The first layer typically is backup power from batteries (or
from
an alternative immediately available energy source, such a flywheel that is
kept
running and is attached to a generator), which provides power immediately when
the power mains fail and keeps the server center running. If the power failure
is
brief, and the power mains return quickly (e.g., within a minute), then the
batteries are all that is needed to keep the server center running. But if the
power
failure is for a longer period of time, then typically generators (e.g.,
diesel-
powered) are started up that take over for the batteries and can run for as
long as
87
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
they have fuel. Such generators are extremely expensive since they must be
capable of producing as much power as the server center normally gets from the
power mains.
[0227] In one embodiment, each of the hosting services HS1-HS5 share
user data with one another so that if one server center has a power failure,
it can
pause the games and applications that are in process, and then transfer the
game
or application state data from each server 402 to servers 402 at other server
centers, and then will notify the client 415 of each user to direct it
communications to the new server 402. Given that such situations occur
infrequently, it may be acceptable to transfer a user to a hosting service
server
center which is not able to provide optimal latency (i.e., the user will
simply have
to tolerate higher latency for the duration of the power failure), which will
allow
for a much wider range of options for transferring users. For example, given
the
time zone differences across the US, users on the East Coast may be going to
sleep at 11:30PM while users on the West Coast at 8:30PM are starting to peak
in
video game usage. If there is a power failure in a hosting service server
center on
the West Coast at that time, there may not be enough West Coast servers 402 at
other hosting service server centers to handle all of the users. In such a
situation,
some of the users can be transferred to hosting service server centers on the
East
Coast which have available servers 402, and the only consequence to the users
would be higher latency. Once the users have been transferred from the server
center that has lost power, the server center can then commence an orderly
shutdown of its servers and equipment, such that all of the equipment has been
shut down before the batteries (or other immediate power backup) is exhausted.
In this way, the cost of a generator for the server center can be avoided.
[0228] In one embodiment, during times of heavy loading of the hosting
service 210 (either due to peak user loading, or because one or more server
centers have failed) users are transferred to other server centers on the
basis of the
latency requirements of the game or application they are using. So, users
using
88
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
games or applications that require low latency would be given preference to
available low latency server connections when there is a limited supply.
[0229] HOSTING SERVICE FEATURES
[0230] Figure 15 illustrates an embodiment of components of a server
center for hosting service 210 utilized in the following feature descriptions.
As
with the hosting service 210 illustrated in Figure 2a, the components of this
server center are controlled and coordinated by a hosting service 210 control
system 401 unless otherwise qualified.
[0231] Inbound internet traffic 1501 from user clients 415 is directed to
inbound routing 1502. Typically, inbound internet traffic 1501 will enter the
server center via a high-speed fiber optic connection to the Internet, but any
network connection means of adequate bandwidth, reliability and low latency
will
suffice. Inbound routing 1502 is a system of network (the network can be
implemented as an Ethernet network, a fiber channel network, or through any
other transport means) switches and routing servers supporting the switches
which takes the arriving packets and routes each packet to the appropriate
application/game ("app/game") server 1521-1525. In one embodiment, a packet
which is delivered to a particular app/game server represents a subset of the
data
received from the client and/or may be translated/changed by other components
(e.g., networking components such as gateways and routers) within the data
center. In some cases, packets will be routed to more than one server 1521-
1525
at a time, for example, if a game or application is running on multiple
servers at
once in parallel. RAID array 1511-1512 are connected to the inbound routing
network 1502, such that the app/game servers 1521-1525 can read and write to
the RAID arrays 1511-1512. Further, a RAID array 1515 (which maybe
implemented as multiple RAID arrays) is also connected to the inbound routing
1502 and data from RAID array 1515 can be read from app/game servers 1521-
1525. The inbound routing 1502 may be implemented in a wide range of prior art
network architectures, including a tree structure of switches, with the
inbound
89
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
internet traffic 1501 at its root; in a mesh structure interconnecting all of
the
various devices; or as an interconnected series of subnets, with concentrated
traffic amongst intercommunicating device segregated from concentrated traffic
amongst other devices. One type of network configuration is a SAN which,
although typically used for storage devices, it can also be used for general
high-
speed data transfer among devices. Also, the app/game servers 1521-1525 may
each have multiple network connections to the inbound routing 1502. For
example, a server 1521-1525 may have a network connection to a subnet attached
to RAID Arrays 1511-1512 and another network connection to a subnet attached
to other devices.
[0232] The app/game servers 1521-1525 may all be configured the same,
some differently, or all differently, as previously described in relation to
servers
402 in the embodiment illustrated in Figure 4a. In one embodiment, each user,
when using the hosting service is typically at least one app/game server 1521-
1525. For the sake of simplicity of explanation, we shall assume a given user
is
using app/game server 1521, but multiple servers could be used by one user,
and
multiple users could share a single app/game server 1521-1525. The user's
control input, sent from client 415 as previously described is received as
inbound
Internet traffic 1501, and is routed through inbound routing 1502 to app/game
server 1521. App/game server 1521 uses the user's control input as control
input
to the game or application running on the server, and computes the next frame
of
video and the audio associated with it. App/game server 1521 then outputs the
uncompressed video/audio 1529 to shared video compression 1530. App/game
server may output the uncompressed video via any means, including one or more
Gigabit Ethernet connections, but in one embodiment the video is output via a
DVI connection and the audio and other compression and communication channel
state information is output via a Universal Serial Bus (USB) connection.
[0233] The shared video compression 1530 compresses the uncompressed
video and audio from the app/game servers 1521-1525. The compression maybe
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
implemented entirely in hardware, or in hardware running software. There may a
dedicated compressor for each app/game server 1521-1525, or if the compressors
are fast enough, a given compressor can be used to compress the video/audio
from more than one app/game server 1521-1525. For example, at 60fps a video
frame time is 16.67ms. If a compressor is able to compress a frame in lms,
then
that compressor could be used to compress the video/audio from as many as 16
app/game servers 1521-1525 by taking input from one server after another, with
the compressor saving the state of each video/audio compression process and
switching context as it cycles amongst the video/audio streams from the
servers.
This results in substantial cost savings in compression hardware. Since
different
servers will be completing frames at different times, in one embodiment, the
compressor resources are in a shared pool 1530 with shared storage means
(e.g.,
RAM, Flash) for storing the state of each compression process, and when a
server
1521-1525 frame is complete and ready to be compressed, a control means
determines which compression resource is available at that time, provides the
compression resource with the state of the server's compression process and
the
frame of uncompressed video/audio to compress.
[0234] Note that part of the state for each server's compression process
includes information about the compression itself, such as the previous
frame's
decompressed frame buffer data which may be used as a reference for P tiles,
the
resolution of the video output; the quality of the compression; the tiling
structure;
the allocation of bits per tiles; the compression quality, the audio format
(e.g.,
stereo, surround sound, Dolby AC-3). But the compression process state also
includes communication channel state information regarding the peak data rate
941 and whether a previous frame (as illustrated in Fig 9b) is currently being
output (and as result the current frame should be ignored), and potentially
whether there are channel characteristics which should be considered in the
compression, such as excessive packet loss, which affect decisions for the
compression (e.g., in terms of the frequency of I tiles, etc). As the peak
data rate
91
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
941 or other channel characteristics change over time, as determined by an
app/game server 1521-1525 supporting each user monitoring data sent from the
client 415, the app/game server 1521-1525 sends the relevant information to
the
shared hardware compression 1530.
[0235] The shared hardware compression 1530 also packetizes the
compressed video/audio using means such as those previously described, and if
appropriate, applying FEC codes, duplicating certain data, or taking other
steps to
as to adequately ensure the ability of the video/audio data stream to be
received
by the client 415 and decompressed with as high a quality and reliability as
feasible.
[0236] Some applications, such as those described below, require the
video/audio output of a given app/game server 1521-1525 to be available at
multiple resolutions (or in other multiple formats) simultaneously. If the
app/game server 1521-1525 so notifies the shared hardware compression 1530
resource, then the uncompressed video audio 1529 of that app/game server 1521-
1525 will be simultaneously compressed in different formats, different
resolutions, and/or in different packet/error correction structures. In some
cases,
some compression resources can be shared amongst multiple compression
processes compressing the same video/audio (e.g., in many compression
algorithms, there is a step whereby the image is scaled to multiple sizes
before
applying compression. If different size images are required to be output, then
this
step can be used to serve several compression processes at once). In other
cases,
separate compression resources will be required for each format. In any case,
the
compressed video/audio 1539 of all of the various resolutions and formats
required for a given app/game server 1521-1525 (be it one or many) will be
output at once to outbound routing 1540. In one embodiment the output of the
compressed video/audio 1539 is in UDP format, so it is a unidirectional stream
of
packets.
92
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0237] The outbound routing network 1540 comprises a series of routing
servers and switches which direct each compressed video/audio stream to the
intended user(s) or other destinations through outbound Internet traffic 1599
interface (which typically would connect to a fiber interface to the Internet)
and/or back to the delay buffer 1515, and/or back to the inbound routing 1502,
and/or out through a private network (not shown) for video distribution. Note
that
(as described below) the outbound routing 1540 may output a given video/audio
stream to multiple destinations at once. In one embodiment this is implemented
using Internet Protocol (IP) multicast in which a given UDP stream intended to
be
streamed to multiple destinations at once is broadcasted, and the broadcast is
repeated by the routing servers and switches in the outbound routing 1540. The
multiple destinations of the broadcast may be to multiple users' clients 415
via
the Internet, to multiple app/game servers 1521-1525 through via inbound
routing
1502, and/or to one or more delay buffers 1515. Thus, the output of a given
server 1521-1522 is compressed into one or multiple formats, and each
compressed stream is directed to one or multiple destinations.
[0238] Further, in another embodiment, if multiple app/game servers
1521-1525 are used simultaneously by one user (e.g., in a parallel processing
configuration to create the 3D output of a complex scene) and each server is
producing part of the resulting image, the video output of multiple servers
1521-
1525 can be combined by the shared hardware compression 1530 into a combined
frame, and from that point forward it is handled as described above as if it
came
from a single app/game server 1521-1525.
[0239] Note that in one embodiment, a copy (in at least the resolution or
higher of video viewed by the user) of all video generated by app/game servers
1521-1525 is recorded in delay buffer 1515 for at least some number of minutes
(15 minutes in one embodiment). This allows each user to "rewind" the video
from each session in order to review previous work or exploits (in the case of
a
game). Thus, in one embodiment, each compressed video/audio output 1539
93
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
stream being routed to a user client 415 is also being multicasted to a delay
buffer
1515. When the video/audio is stored on a delay buffer 1515, a directory on
the
delay buffer 1515 provides a cross reference between the network address of
the
app/game server 1521-1525 that is the source of the delayed video/audio and
the
location on the delay buffer 1515 where the delayed video/audio can be found.
[0240] LIVE, INSTANTLY-VIEWABLE, INSTANTLY-PLAYABLE GAMES
[0241] App/game servers 1521-1525 may not only be used for running a
given application or video game for a user, but they may also be used for
creating
the user interface applications for the hosting service 210 that supports
navigation
through hosting service 210 and other features. A screen shot of one such user
interface application is shown in Figure 16, a "Game Finder" screen. This
particular user interface screen allows a user to watch 15 games that are
being
played live (or delayed) by other users. Each of the "thumbnail" video
windows,
such as 1600 is a live video window in motion showing one the video from one
user's game. The view shown in the thumbnail may be the same view that the
user is seeing, or it may be a delayed view (e.g., if a user is playing a
combat
game, a user may not want other users to see where she is hiding and she may
choose to delay any view of her gameplay by a period of time, say 10 minutes).
The view may also be a camera view of a game that is different from any user's
view. Through menu selections (not shown in this illustration), a user may
choose
a selection of games to view at once, based on a variety of criteria. As a
small
sampling of exemplary choices, the user may select a random selection of games
(such as those shown in Figure 16), all of one kind of games (all being played
by
different players), only the top-ranked players of a game, players at a given
level
in the game, or lower-ranked players (e.g., if the player is learning the
basics),
players who are "buddies" (or are rivals), games that have the most number of
viewers, etc.
94
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0242] Note that generally, each user will decide whether the video from
his or her game or application can be viewed by others and, if so, which
others,
and when it may be viewed by others, whether it is only viewable with a delay.
[0243] The app/game server 1521-1525 that is generating the user
interface screen shown in Figure 16 acquires the 15 video/audio feeds by
sending
a message to the app/game server 1521-1525 for each user whose game it is
requesting from. The message is sent through the inbound routing 1502 or
another network. The message will include the size and format of the
video/audio
requested, and will identify the user viewing the user interface screen. A
given
user may choose to select "privacy" mode and not permit any other users to
view
video/audio of his game (either from his point of view or from another point
of
view), or as described in the previous paragraph, a user may choose to allow
viewing of video/audio from her game, but delay the video/audio viewed. A user
app/game server 1521-1525 receiving and accepting a request to allow its
video/audio to be viewed will acknowledge as such to the requesting server,
and
it will also notify the shared hardware compression 1530 of the need to
generate
an additional compressed video stream in the requested format or screen size
(assuming the format and screen size is different than one already being
generated), and it will also indicate the destination for the compressed video
(i.e.,
the requesting server). If the requested video/audio is only delayed, then the
requesting app/game server 1521-1525 will be so notified, and it will acquire
the
delayed video/audio from a delay buffer 1515 by looking up the video/audio's
location in the directory on the delay buffer 1515 and the network address of
the
app/game server 1521-1525 that is the source of the delayed video/audio. Once
all of these requests have been generated and handled, up to 15 live thumbnail-
sized video streams will be routed from the outbound routing 1540 to the
inbound
routing 1502 to the app/game server 1521-1525 generating the user interface
screen, and will be decompressed and displayed by the server. Delayed
video/audio streams may be in too large a screen size, and if so, the app/game
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
server 1521-1525 will decompress the streams and scale down the video streams
to thumbnail size. In one embodiment, requests for audio/video are sent to
(and
managed by) a central "management" service similar to the hosting service
control system of Figure 4a (not shown in Figure 15) which then redirects the
requests to the appropriate app/game server 1521-1525. Moreover, in one
embodiment, no request may be required because the thumbnails are "pushed" to
the clients of those users that allow it.
[0244] The audio from 15 games all mixed simultaneously might create a
cacophony of sound. The user may choose to mix all of the sounds together in
this way (perhaps just to get a sense of the "din" created by all the action
being
viewed), or the user may choose to just listen to the audio from one game at a
time. The selection of a single game is accomplished by moving the yellow
selection box 1601 to a given game (the yellow box movement can be
accomplished by using arrow keys on a keyboard, by moving a mouse, by
moving a joystick, or by pushing directional buttons on another device such as
a
mobile phone). Once a single game is selected, just the audio from that game
plays. Also, game information 1602 is shown. In the case of this game, for
example, the publisher logo ("EA") and the game logo, "Need for Speed Carbon"
and an orange horizontal bar indicates in relative terms the number of people
playing or viewing the game at that particular moment (many, in this case, so
the
game is "Hot"). Further "Stats" are provided, indicating that there are 145
players
actively playing 80 different instantiations of the Need for Speed Game (i.e.,
it
can be played either by an individual player game or multiplayer game), and
there
are 680 viewers (of which this user is one). Note that these statistics (and
other
statistics) are collected by hosting service control system 401 and are stored
on
RAID arrays 1511-1512, for keeping logs of the hosting service 210 operation
and for appropriately billing users and paying publishers who provide content.
Some of the statistics are recorded due to actions by the service control
system
401, and some are reported to the service control system 401 by the individual
96
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
app/game server 1521-1525. For example, the app/game server 1521-1525
running this Game Finder application sends messages to the hosting service
control system 401 when games are being viewed (and when they are ceased to
be viewed) so that it may update the statistics of how many games are in view.
Some of the statistics are available for user interface applications such as
this
Game Finder application.
[0245] If the user clicks an activation button on their input device, they
will see the thumbnail video in the yellow box zoom up while it remains live
to
full screen size. This effect is shown in process in Figure 17. Note that
video
window 1700 has grown in size. To implement this effect, the app/game server
1521-1525 requests from the app/game server 1521-1525 running the game
selected to have a copy of the video stream for a full screen size (at the
resolution
of the user's display device 422) of the game routed to it. The app/game
server
1521-1525 running the game notifies the shared hardware compressor 1530 that a
thumbnail-sized copy of the game is no longer needed (unless another app/game
server 1521-1525 requires such a thumbnail), and then it directs it to send a
full-
screen size copy of the video to the app/game server 1521-1525 zooming the
video. The user playing the game may or may not have a display device 422 that
is the same resolution as that of the user zooming up the game. Further, other
viewers of the game may or may not have display devices 422 that are the same
resolution as the user zooming up the game (and may have different audio
playback means, e.g., stereo or surround sound). Thus, the shared hardware
compressor 1530 determines whether a suitable compressed video/audio stream is
already being generated that meets the requirements of the user requesting the
video/audio stream and if one does exist, it notifies the outbound routing
1540 to
route a copy of the stream to the app/game server 1521-1525 zooming the video,
and if not compresses another copy of the video that is suitable for that user
and
instructs the outbound routing to send the stream back to the inbound routing
1502 and the app/game server 1521-1525 zooming the video. This server, now
97
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
receiving a full screen version of the selected video will decompress it and
gradually scale it up to full size.
[0246] Figure 18 illustrates how the screen looks after the game has
completely zoomed up to full screen and the game is shown at the full
resolution
of the user's display device 422 as indicated by the image pointed to by arrow
1800. The app/game server 1521-1525 running the game finder application sends
messages to the other app/game servers 1521-1525 that had been providing
thumbnails that they are no longer needed and messages to the hosting service
control server 401 that the other games are no longer being viewed. At this
point
the only display it is generating is an overlay 1801 at the top of the screen
which
provides information and menu controls to the user. Note that as this game has
progressed, the audience has grown to 2,503 viewers. With so many viewers,
there are bound to be many viewers with display devices 422 that have the same
or nearly the resolution (each app/game server 1521-1525 has the ability to
scale
the video for adjusting the fitting).
[0247] Because the game shown is a multiplayer game, the user may
decide to join the game at some point. The hosting service 210 may or may not
allow the user to join the game for a variety of reasons. For example, the
user
may have to pay to play the game and choose not to, the user may not have
sufficient ranking to join that particular game (e.g., it would not be
competitive
for the other players), or the user's Internet connection may not have low
enough
latency to allow the user to play (e.g., there is not a latency constraint for
viewing
games, so a game that is being played far away (indeed, on another continent)
can
be viewed without latency concerns, but for a game to be played, the latency
must
be low enough for the user to (a) enjoy the game, and (b) be on equal footing
with
the other players who may have lower latency connections). If the user is
permitted to play, then app/game server 1521-1525 that had been providing the
Game Finder user interface for the user will request that the hosting service
control server 401 initiate (i.e., locate and start up) an app/game server
1521-1525
98
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
that is suitably configured for playing the particular game to load the game
from a
RAID array 1511-1512, and then the hosting service control server 401 will
instruct the inbound routing 1502 to transfer the control signals from the
user to
the app/game game server now hosting the game and it will instruct the shared
hardware compression 1530 to switch from compressing the video/audio from the
app/game server that had been hosting the Game Finder application to
compressing the video/audio from the app/game server now hosting the game.
The vertical sync of the Game Finder app/game service and the new app/game
server hosting the game are not synchronized, and as a result there is likely
to be
a time difference between the two syncs. Because the shared video compression
hardware 1530 will begin compressing video upon an app/game server 1521-
1525 completing a video frame, the first frame from the new server may be
completed sooner than a full frame time of the old server, which may be before
the prior compressed frame completing its transmission (e.g., consider
transmit
time 992 of Figure 9b: if uncompressed frame 3 963 were completed half a frame
time early, it would impinge upon the transmit time 992). In such a situation
the
shared video compression hardware 1530 will ignore the first frame from the
new
server (e.g., like Frame 4 964 is ignored 974), and the client 415 will hold
the last
frame from the old server an extra frame time, and the shared video
compression
hardware 1530 will begin compressing the next frame time video from the new
app/game server hosting the game. Visually, to the user, the transition from
one
app/game server to the other will be seamless. The hosting service control
server
401 will then notify app/game game server 1521-1525 that had been hosting the
Game Finder to switch to an idle state, until it is needed again.
[0248] The user then is able to play the game. And, what is exceptional is
the game will play perceptually instantly (since it will have loaded onto the
app/game game server 1521-1525 from a Raid array 1511-1512 at gigabit/second
speed), and the game will be loaded onto a server exactly suited for the game
together with an operating system exactly configured for the game with the
ideal
99
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
drivers, registry configuration (in the case of Windows), and with no other
applications running on the server that might compete with the game's
operation.
[0249] Also, as the user progresses through the game, each of the
segments of the game will load into the server at gigabit/second speed (i.e.,
1
gigabyte loads in 8 seconds) from the RAID array 1511-1512, and because of the
vast storage capacity of the RAID array 1511-1512 (since it is a shared
resource
among many users, it can be very large, yet still be cost effective) geometry
setup
or other game segment setup can be pre-computed and stored on the RAID array
1511-1512 and loaded extremely rapidly. Moreover, because the hardware
configuration and computational capabilities of each app/game server 1521-1525
is known, pixel and vertex shaders can be pre-computed.
[0250] Thus, the game will start up almost instantly, it will run in an ideal
environment, and subsequent segments will load almost instantly.
[0251] But, beyond these advantages, the user will be able to view others
playing the game (via the Game Finder, previously described and other means)
and both decide if the game is interesting, and if so, learn tips from
watching
others. And, the user will be able to demo the game instantly, without having
to
wait for a large download and/or installation, and the user will be able to
play the
game instantly, perhaps on a trial basis for a smaller fee, or on a longer
term
basis. And, the user will be able to play the game on a Windows PC, a
Macintosh,
on a television set, at home, when traveling, and even on a mobile phone, with
a
low enough latency wireless connection. And, this can all be accomplished
without ever physically owning a copy of the game.
[0252] As mentioned previously, the user can decide to not allow his
gameplay to be viewable by others, to allow his game to be viewable after a
delay, to allow his game to be viewable by selected users, or to allow his
game to
be viewable by all users. Regardless, the video/audio will be stored, in one
embodiment, for 15 minutes in a delay buffer 1515, and the user will be able
to
"rewind" and view his prior game play, and pause, play it back slowly, fast
100
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
forward, etc., just as he would be able to do had he been watching TV with a
Digital Video Recorder (DVR). Although in this example, the user is playing a
game, the same "DVR" capability is available if the user is using an
application.
This can be helpful in reviewing prior work and in other applications as
detailed
below. Further, if the game was designed with the capability of rewinding
based
on utilizing game state information, such that the camera view can be changed,
etc., then this "3D DVR" capability will also be supported, but it will
require the
game to be designed to support it. The "DVR" capability using a delay buffer
1515 will work with any game or application, limited of course, to the video
that
was generated when the game or application was used, but in the case of games
with 3D DVR capability, the user can control a "fly through" in 3D of a
previously played segment, and have the delay buffer 1515 record the resulting
video and have the game state of the game segment record. Thus, a particular
"fly-through" will be recorded as compressed video, but since the game state
will
also be recorded, a different fly-through will be possible at a later date of
the
same segment of the game.
[0253] As described below, users on the hosting service 210 will each
have a User Page, where they can post information about themselves and other
data. Among of the things that users will be able to post are video segments
from
game play that they have saved. For example, if the user has overcome a
particularly difficult challenge in a game, the user can "rewind" to just
before the
spot where they had their great accomplishment in the game, and then instruct
the
hosting service 210 to save a video segment of some duration (e.g., 30
seconds)
on the user's User Page for other users to watch. To implement this, it is
simply a
matter of the app/game server 1521-1525 that the user is using to playback the
video stored in a delay buffer 1515 to a RAID array 1511-1512 and then index
that video segment on the user's User Page.
101
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0254] If the game has the capability of 3D DVR, as described above,
then the game state information required for the 3D DVR can also be recorded
by
the user and made available for the user's User Page.
[0255] In the event that a game is designed to have "spectators" (i.e.,
users that are able to travel through the 3D world and observe the action
without
participating in it) in addition to active players, then the Game Finder
application
will enable users to join games as spectators as well as players. From an
implementation point of view, there is no difference to the hosting system 210
to
if a user is a spectator instead of an active player. The game will be loaded
onto
an app/game server 1521-1525 and the user will be controlling the game (e.g.,
controlling a virtual camera that views into the world). The only difference
will
be the game experience of the user.
[0256] MULTIPLE USER COLLABORATION
[0257] Another feature of the hosting service 210 is the ability to for
multiple users to collaborate while viewing live video, even if using widely
disparate devices for viewing. This is useful both when playing games and when
using applications.
[0258] Many PCs and mobile phones are equipped with video cameras
and have the capability to do real-time video compression, particularly when
the
image is small. Also, small cameras are available that can be attached to a
television, and it is not difficult to implement real-time compression either
in
software or using one of many hardware compression devices to compress the
video. Also, many PCs and all mobile phones have microphones, and headsets are
available with microphones.
[0259] Such cameras and/or microphones, combined with local
video/audio compression capability (particularly employing the low latency
video
compression techniques described herein) will enable a user to transmit video
and/or audio from the user premises 211 to the hosting service 210, together
with
the input device control data. When such techniques are employed, then a
102
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
capability illustrated in Figure 19 is achievable: a user can have his video
and
audio 1900 appear on the screen within another user's game or application.
This
example is a multiplayer game, where teammates collaborate in a car race. A
user's video/audio could be selectively viewable / hearable only by their
teammates. And, since there would be effectively no latency, using the
techniques
described above the players would be able to talk or make motions to each
other
in real-time without perceptible delay.
[0260] This video/audio integration is accomplished by having the
compressed video and/or audio from a user's camera/microphone arrive as
inbound internet traffic 1501. Then the inbound routing 1502 routes the video
and/or audio to the app/game game servers 1521-1525 that are permitted to
view/hear the video and/or audio. Then, the users of the respective app/game
game servers 1521-1525 that choose to use the video and/or audio decompress it
and integrate as desired to appear within the game or application, such as
illustrated by 1900.
[0261] The example of Figure 19 shows how such collaboration is used in
a game, but such collaboration can be an immensely powerful tool for
applications. Consider a situation where a large building is being designed
for
New York city by architects in Chicago for a real estate developer based in
New
York, but the decision involves a financial investor who is traveling and
happens
to be in an airport in Miami, and a decision needs to be made about certain
design
elements of the building in terms of how it fits in with the buildings near
it, to
satisfy both the investor and the real estate developer. Assume the
architectural
firm has a high resolution monitor with a camera attached to a PC in Chicago,
the
real estate developer has a laptop with a camera in New York, and the investor
has a mobile phone with a camera in Miami. The architectural firm can use the
hosting service 210 to host a powerful architectural design application that
is
capable of highly realistic 3D rendering, and it can make use of a large
database
of the buildings in New York City, as well as a database of the building under
103
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
design. The architectural design application will execute on one, or if it
requires a
great deal of computational power on several, of the app/game servers 1521-
1525. Each of the 3 users at disparate locations will connect to the hosting
service
210, and each will have a simultaneous view of the video output of the
architectural design application, but it will be will appropriately sized by
the
shared hardware compression 1530 for the given device and network connection
characteristics that each user has (e.g., the architectural firm may see a
2560x1440 60fps display through a 20Mbps commercial Internet connection, the
real estate developer in New York may see a 1280x720 60fps image over a 6
Mbps DSL connection on his laptop, and the investor may see a 320x 180 60fps
image over a 250Kbps cellular data connection on her mobile phone. Each party
will hear the voice of the other parties (the conference calling will be
handled by
any of many widely available conference calling software package in the
app/game server(s) 1521-1525) and, through actuation of a button on a user
input
device, a user will be able to make video appear of themselves using their
local
camera. As the meeting proceeds, the architects will be able to show what the
build looks like as they rotate it and fly by it next to the other building in
the area,
with extremely photorealistic 3D rendering, and the same video will be visible
to
all parties, at the resolution of each party's display device. It won't matter
that
none of the local devices used by any party is incapable of handling the 3D
animation with such realism, let alone downloading or even storing the vast
database required to render the surrounding buildings in New York City. From
the point of view of each of the users, despite the distance apart, and
despite the
disparate local devices they simply will have a seamless experience with an
incredible degree of realism. And, when one party wants their face to be seen
to
better convey their emotional state, they can do so. Further, if either the
real
estate develop or the investor want to take control of the architectural
program
and use their own input device (be it a keyboard, mouse, keypad or touch
screen),
they can, and it will respond with no perceptual latency (assuming their
network
104
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
connection does not have unreasonable latency). For example, in the case of
the
mobile phone, if the mobile phone is connected to a WiFi network at the
airport,
it will have very low latency. But if it is using the cellular data networks
available
today in the US, it probably will suffer from a noticeable lag. Still, for
most of the
purposes of the meeting, where the investor is watching the architects control
the
building fly-by or for talking of video teleconferencing, even cellular
latency
should be acceptable.
[0262] Finally, at the end of the collaborative conference call, the real
estate developer and the investor will have made their comments and signed off
from the hosting service, the architectural firm will be able to "rewind" the
video
of the conference that has been recorded on a delay buffer 1515 and review the
comments, facial expressions and/or actions applied to the 3D model of the
building made during the meeting. If there are particular segments they want
to
save, those segments of video/audio can be moved from delay buffer 1515 to a
RAID array 1511-1512 for archival storage and later playback.
[0263] Also, from a cost perspective, if the architects only need to use the
computation power and the large database of New York City for a 15 minute
conference call, they need only pay for the time that the resources are used,
rather
than having to own high powered workstations and having to purchase an
expensive copy of a large database.
[0264] VIDEO-RICH COMMUNITY SERVICES
[0265] The hosting service 210 enables an unprecedented opportunity for
establishing video-rich community services on the Internet. Figure 20 shows an
exemplary User Page for a game player on the hosting service 210. As with the
Game Finder application, the User Page is an application that runs on one of
the
app/game servers 1521-1525. All of the thumbnails and video windows on this
page show constantly moving video (if the segments are short, they loop).
[0266] Using a video camera or by uploading video, the user (whose
username is "KILLHAZARD") is able to post a video of himself 2000 that other
105
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
users can view. The video is stored on a RAID array 1511-1512. Also, when
other users come to KILLHAZARD's User Page, if KILLHAZARD is using the
hosting service 210 at the time, live video 2001 of whatever he is doing
(assuming he permits users viewing his User Page to watch him) will be shown.
This will be accomplished by app/game server 1521-1525 hosting the User Page
application requesting from the service control system 401 whether
KILLHAZARD is active and if so, the app/game server 1521-1525 he is using.
Then, using the same methods used by the Game Finder application, a
compressed video stream in a suitable resolution and format will be sent to
the
app/game server 1521-1525 running the User Page application and it will be
displayed. If a user selects the window with KILLHAZARD's live gameplay, and
then appropriately clicks on their input device, the window will zoom up
(again
using the same methods as the Game Finder applications, and the live video
will
fill the screen, at the resolution of the watching user's display device 422,
appropriate for the characteristics of the watching user's Internet
connection.
[0267] A key advantage of this over prior art approaches is the user
viewing the User Page is able to see a game played live that the user does not
own, and may very well not have a local computer or game console capable of
playing the game. It offers a great opportunity for the user to see the user
shown
in the User Page "in action" playing games, and it is an opportunity to learn
about
a game that the viewing user might want to try or get better at.
[0268] Camera-recorded or uploaded video clips from KILLHAZARD's
buddies 2002 are also shown on the User Page, and underneath each video clip
is
text that indicates whether the buddy is online playing a game (e.g., six-shot
is
playing the game "Eragon" and MrSnuggles99 is Offline, etc.). By clicking on a
menu item (not shown) the buddy video clips switch from showing recorded or
uploaded videos to live video of what the buddies who are currently playing
games on the hosting service 210 are doing at that moment in their games. So,
it
becomes a Game Finder grouping for buddies. If a buddy's game is selected and
106
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
the user clicks on it, it will zoom up to full screen, and the user will be
able to
watch the game played full screen live.
[0269] Again, the user viewing the buddy's game does not own a copy of
the came, nor the local computing/game console resources to play the game. The
game viewing is effectively instantaneous.
[0270] As previously described above, when a user plays a game on the
hosting service 210, the user is able to "rewind" the game and find a video
segment he wants to save, and then saves the video segment to his User Page.
These are called "Brag Clips". The video segments 2003 are all Brag Clips 2003
saved by KILLHAZARD from previous games that he has played. Number 2004
shows how many times a Brag Clip has been viewed, and when the Brag Clip is
viewed, users have an opportunity to rate them, and the number of orange
keyhole-shaped icons 2005 indicate how high the rating is. The Brag Clips 2003
loop constantly when a user views the User Page, along with the rest of the
video
on the page. If the user selects and clicks on one of the Brag Clips 2003, it
zooms
up to present the Brag Clip 2003, along with DVR controls to allow the clip to
be
played, paused, rewound, fast-forwarded, stepped through, etc.
[0271] The Brag Clip 2003 playback is implemented by the app/game
server 1521-1525 loading the compressed video segment stored on a RAID array
1511-1512 when the user recorded the Brag Clip and decompressing it and
playing it back.
[0272] Brag Clips 2003 can also be "3D DVR" video segments (i.e., a
game state sequence from the game that can be replayed and allows the user to
change the camera viewpoint) from games that support such capability. In this
case the game state information is stored, in addition to a compressed video
recording of the particular "fly through" the user made when the game segment
was recorded. When the User Page is being viewed, and all of the thumbnails
and
video windows are constantly looping, a 3D DVR Brag Clip 2003 will constantly
loop the Brag Clip 2003 that was recorded as compressed video when the user
107
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
recorded the "fly through" of the game segment. But, when a user selects a 3D
DVR Brag Clip 2003 and clicks on it, in addition to the DVR controls to allow
the compressed video Brag Clip to be played, the user will be able to click on
a
button that gives them 3D DVR capability for the game segment. They will be
able to control a camera "fly through" during the game segment on their own,
and, if they wish (and the user who owns the user page so allows it) they will
be
able to record an alternative Brag Clip "fly through" in compressed video form
will then be available to other viewers of the user page (either immediately,
or
after the owner of the user page has a chance to the review the Brag Clip).
[0273] This 3D DVR Brag Clip 2003 capability is enabled by activating
the game that is about to replay the recorded game state information on
another
app/game server 1521-1525. Since the game can be activated almost
instantaneously (as previously described) it is not difficult to activate it,
with its
play limited to the game state recorded by the Brag Clip segment, and then
allow
the user to do a "fly through" with a camera while recording the compressed
video to a delay buffer 1515. Once the user has completed doing the "fly
through" the game is deactivated.
[0274] From the user's point of view, activating a "fly through" with a 3D
DVR Brag Clip 2003 is no more effort than controlling the DVR controls of a
linear Brag Clip 2003. They may know nothing about the game or even how to
play the game. They are just a virtual camera operator peering into a 3D world
during a game segment recorded by another.
[0275] Users will also be able to overdub their own audio onto Brag Clips
that is either recorded from microphones or uploaded. In this way, Brag Clips
can
be used to create custom animations, using characters and actions from games.
This animation technique is commonly known as "machinima".
[0276] As users progress through games, they will achieve differing skill
levels. The games played will report the accomplishments to the service
control
system 401, and these skill levels will be shown on User Pages.
108
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0277] INTERACTIVE ANIMATED ADVERTISEMENTS
[0278] Online advertisements have transitioned from text, to still images,
to video, and now to interactive segments, typically implemented using
animation
thin clients like Adobe Flash. The reason animation thin clients are used is
that
users typically have little patience to be delayed for the privilege of have a
product or service pitched to them. Also, thin clients run on very low-
performance PCs and as such, the advertiser can have a high degree of
confidence
that the interactive ad will work properly. Unfortunately, animation thin
clients
such as Adobe Flash are limited in the degree of interactivity and the
duration of
the experience (to mitigate download time).
[0279] Figure 21 illustrates an interactive advertisement where the user is
to select the exterior and interior colors of a car while the car rotates
around in a
showroom, while real-time ray tracing shows how the car looks. Then the user
chooses an avatar to drive the car, and then the user can take the car for a
drive
either on a race track, or through an exotic locale such as Monaco. The user
can
select a larger engine, or better tires, and then can see how the changed
configuration affects the ability of the car to accelerate or hold the road.
[0280] Of course, the advertisement is effectively a sophisticated 3D
video game. But for such an advertisement to be playable on a PC or a video
game console it would require perhaps a 100MB download and, in the case of the
PC, it might require the installation of special drivers, and might not run at
all if
the PC lacks adequate CPU or GPU computing capability. Thus, such
advertisements are impractical in prior art configurations.
[0281] In the hosting service 210, such advertisements launch almost
instantly, and run perfectly, no matter what the user's client 415
capabilities are.
So, they launch more quickly than thin client interactive ads, are vastly
richer in
the experience, and are highly reliable.
109
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0282] STREAMING GEOMETRY DURING REAL-TIME ANIMATION
[0283] RAID array 1511-1512 and the inbound routing 1502 can provide
data rates that are so fast and with latencies so low that it is possible to
design
video games and applications that rely upon the RAID array 1511-1512 and the
inbound routing 1502 to reliably deliver geometry on-the-fly in the midst of
game
play or in an application during real-time animation (e.g., a fly-through with
a
complex database.
[0284] With prior art systems, such as the video game system shown in
Figure 1, the mass storage devices available, particularly in practical home
devices, are far too slow to stream geometry in during game play except in
situations where the required geometry was somewhat predictable. For example,
in a driving game where there is a specified roadway, geometry for buildings
that
are coming into view can be reasonable well predicted and the mass storage
devices can seek in advance to the location where the upcoming geometry is
located.
[0285] But in a complex scene with unpredictable changes (e.g., in a
battle scene with complex characters all around) if RAM on the PC or video
game
system is completely filled with geometry for the objects currently in view,
and
then the user suddenly turns their character around to view what is behind
their
character, if the geometry has not been pre-loaded into RAM, then there may be
a
delay before it can be displayed.
[0286] In the hosting service 210, the RAID arrays 1511-1512 can stream
data in excess of Gigabit Ethernet speed, and with a SAN network, it is
possible
to achieve 10 gigabit/second speed over 10 Gigabit Ethernet or over other
network technologies. 10 gigabits/second will load a gigabyte of data in less
that
a second. In a 60fps frame time (16.67ms), approximately 170 megabits (21MB)
of data can be loaded. Rotating media, of course, even in a RAID configuration
will still incur latencies greater than a frame time, but Flash-based RAID
storage
will eventually be as large as rotating media RAID arrays and will not incur
such
110
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
high latency. In one embodiment, massive RAM write-through caching is used to
provide very low latency access.
[0287] Thus, with sufficiently high network speed, and sufficiently low
enough latency mass storage, geometry can be streamed into app/game game
servers 1521-1525 as fast as the CPUs and/or GPUs can process the 3D data. So,
in the example given previously, where a user turns their character around
suddenly and looks behind, the geometry for all of the characters behind can
be
loaded before the character completes the rotation, and thus, to the user, it
will
seem as if he or she is in a photorealistic world that is as real as live
action.
[0288] As previously discussed, one of the last frontiers in photorealistic
computer animation is the human face, and because of the sensitivity of the
human eye to imperfections, the slightest error from a photoreal face can
result in
a negative reaction from the viewer. Figure 22 shows how a live performance
captured using ContourTM Reality Capture Technology (subject of co-pending
applications: "Apparatus and method for capturing the motion of a performer,"
Ser. No. 10/942,609, Filed September 15, 2004; "Apparatus and method for
capturing the expression of a performer," Ser. No. 10/942,413 Filed September
15, 2004; "Apparatus and method for improving marker identification within a
motion capture system," Ser. No. 11/066,954, Filed February 25, 2005;
"Apparatus and method for performing motion capture using shutter
synchronization," Ser. No. 11/077,628, Filed March 10, 2005; "Apparatus and
method for performing motion capture using a random pattern on capture
surfaces," Ser. No. 11/255,854, Filed October 20, 2005; "System and method for
performing motion capture using phosphor application techniques," Ser. No.
11/449,131, Filed June 7, 2006; "System and method for performing motion
capture by strobing a fluorescent lamp," Ser. No. 11/449,043, Filed June 7,
2006;
"System and method for three dimensional capture of stop-motion animated
characters," Ser. No. 11/449,127, Filed June 7, 2006", each of which is
assigned
to the assignee of the present CIP application) results in a very smooth
captured
111
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
surface, then a high polygon-count tracked surface (i.e., the polygon motion
follows the motion of the face precisely). Finally, when the video of the live
performance is mapped on the tracked surface to produce a textured surface, a
photoreal result is produced.
[0289] Although current GPU technology is able to render the number of
polygons in the tracked surface and texture and light the surface in real-
time, if
the polygons and textures are changing every frame time (which will produce
the
most photoreal results) it will quickly consume all the available RAM of a
modern PC or video game console.
[0290] Using the streaming geometry techniques described above, it
becomes practical to continuously feed geometry into the app/game game servers
1521-1525 so that they can animate photoreal faces continuously, allowing the
creation of video games with faces that are almost indistinguishable from live
action faces.
[0291] INTEGRATION OF LINEAR CONTENT WITH INTERACTIVE
FEATURES
[0292] Motion pictures, television programming and audio material
(collectively, "linear content" is widely available to home and office users
in
many forms. Linear content can be acquired on physical media, like CD, DVD,
HD-DVD and Blu-ray media. It also can be recorded by DVRs from satellite and
cable TV broadcast. And, it is available as pay-per-view (PPV) content through
satellite and cable TV and as video-on-demand (VOD) on cable TV.
[0293] Increasingly linear content is available through the Internet, both
as downloaded and as streaming content. Today, there really is not one place
to
go to experience all of the features associated with linear media. For
example,
DVDs and other video optical media typically have interactive features not
available elsewhere, like director's commentaries, "making of featurettes,
etc.
Online music sites have cover art and song information generally not available
on
CDs, but not all CDs are available online. And Web sites associating with
112
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
television programming often have extra features, blogs and sometimes
comments from the actors or creative staff.
[0294] Further, with many motion pictures or sports events, there are
often video games that are released (in the case of motion pictures) often
together
with the linear media or (in the case of sports) may be closely tied to real-
world
events (e.g., the trading of players).
[0295] Hosting service 210 is well suited for the delivery of linear content
in linking together the disparate forms of related content. Certainly,
delivering
motion pictures is no more challenging that delivering highly interactive
video
games, and the hosting service 210 is able to deliver linear content to a wide
range of devices, in the home or office, or to mobile devices. Figure 23 shows
an
exemplary user interface page for hosting service 210 that shows a selection
of
linear content.
[0296] But, unlike most linear content delivery system, hosting service
210 is also able to deliver related interactive components (e.g., the menus
and
features on DVDs, the interactive overlays on HD-DVDs, and the Adobe Flash
animation (as explained below) on Web sites. Thus, the client device 415
limitations no longer introduce limitations as to which features are
available.
[0297] Further, the hosting system 210 is able to link together linear
content with video game content dynamically, and in real-time. For example, if
a
user is watching a Quidditch match in a Harry Potter movie, and decides she
would like to try playing Quidditch, she can just click a button and the movie
will
pause and immediately she will be transported to the Quidditch segment of a
Harry Potter video game. After playing the Quidditch match, another click of a
button, and the movie will resume instantly.
[0298] With photoreal graphics and production technology, where the
photographically-captured video is indistinguishable from the live action
characters, when a user makes a transition from a Quidditch game in a live
action
movie to a Quidditch game in a video game on a hosting service as described
113
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
herein, the two scenes are virtually indistinguishable. This provides entirely
new
creative options for directors of both linear content and interactive (e.g.,
video
game) content as the lines between the two worlds become indistinguishable.
[0299] Utilizing the hosting service architecture shown in Fig. 14 the
control of the virtual camera in a 3D movie can be offered to the viewer. For
example, in a scene that takes place within a train car, it would be possible
to
allow the viewer to control the virtual camera and look around the car while
the
story progresses. This assumes that all of the 3D objects ("assets") in the
car are
available as well as an adequate a level of computing power capable of
rendering
the scenes in real-time as well as the original movie.
[0300] And even for non-computer generated entertainment, there are
very exciting interactive features that can be offered. For example, the 2005
motion picture "Pride and Prejudice" had many scenes in ornate old English
mansions. For certain mansion scenes, the user may pause the video and then
control the camera to take a tour of the mansion, or perhaps the surrounding
area.
To implement this, a camera could be carried through the mansion with a fish-
eye
lens as it keeps track of its position, much like prior art Apple, Inc.
QuickTime
VR is implemented. The various frames would then be transformed so the images
are not distorted, and then stored on RAID array 1511-1512 along with the
movie, and played back when the user chooses to go on a virtual tour.
[03011 With sports events, a live sports event, such as a basketball game,
may be streamed through the hosting service 210 for users to watch, as they
would for regular TV. After users watched a particular play, a video game of
the
game (eventually with basketball players looking as photoreal as the real
players)
could come up with the players starting in the same position, and the users
(perhaps each taking control of one player) could redo the play to see if they
could do better than the players.
[0302] The hosting service 210 described herein is extremely well-suited
to support this futuristic world because it is able to bring to bear computing
114
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
power and mass storage resources that are impractical to install in a home or
in
most office settings, and also it's computing resources are always up-to-date,
with
the latest computing hardware available, whereas in a home setting, there will
always be homes with older generation PCs and video games. And, in the hosting
service 210, all of this computing complexity is hidden from the user, so even
though they may be using very sophisticated systems, from the user's point of
view, it is a simple as changing channels on a television. Further, the users
would
be able to access all of the computing power and the experiences the computing
power would bring from any client 415.
[0303] MULTIPLAYER GAMES
[0304] To the extent the game is a multiplayer game, then it will be able
communicate both to app/game game servers 1521-1525 through the inbound
routing 1502 network and, with a network bridge to the Internet (not shown)
with
servers or game machines that are not running in the hosting service 210. When
playing multiplayer games with computers on the general Internet, then the
app/game game servers 1521-1525 will have the benefit of extremely fast access
to the Internet (compared to if the game was running on a server at home), but
they will be limited by the capabilities of the other computers playing the
game
on slower connections, and also potentially limited by the fact that the game
servers on the Internet were designed to accommodate the least common
denominator, which would be home computers on relatively slow consumer
Internet connections.
[0305] But when a multiplayer game is played entirely within a hosting
service 210 server center, then a world of difference is achievable. Each
app/game game server 1521-1525 hosting a game for a user will be
interconnected with other app/game game servers 1521-1525 as well as any
servers that are hosting the central control for the multiplayer game with
extremely high speed, extremely low latency connectivity and vast, very fast
storage arrays. For example, if Gigabit Ethernet is used for the inbound
routing
115
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
1502 network, then the app/game game servers 1521-1525 will be
communicating among each other and communicating to any servers hosting the
central control for the multiplayer game at gigabit/second speed with
potentially
only Ims of latency or less. Further, the RAID arrays 1511-1512 will be able
to
respond very rapidly and then transfer data at gigabit/second speeds. As an
example, if a user customizes a character in terms of look and accoutrements
such
that the character has a large amount of geometry and behaviors that are
unique to
the character, with prior art systems limited to the game client running in
the
home on a PC or game console, if that character were to come into view of
another user, the user would have to wait until a long, slow download
completes
so that all of the geometry and behavior data loads into their computer.
Within the
hosting service 210, that same download could be over Gigabit Ethernet, served
from a RAID array 1511-1512 at gigabit/second speed. Even if the home user had
an 8Mbps Internet connection (which is extremely fast by today's standards),
Gigabit Ethernet is 100 times faster. So, what would take a minute over a fast
Internet connection, would take less than a second over Gigabit Ethernet.
[0306] TOP PLAYER GROUPINGS AND TOURNAMENTS
[0307] The Hosting Service 210 is extremely well-suited for tournaments.
Because no game is running in a local client, there is no opportunity for
users to
cheat. Also, because of the ability of the output routing 1540 to multicast
the
UDP streams, the Hosting Service is 210 is able to broadcast the major
tournaments to thousands of people in the audience at once.
[0308] In fact, when there are certain video streams that are so popular
that thousands of users are receiving the same stream (e.g., showing views of
a
major tournament), it may be more efficient to send the video stream to a
Content
Delivery Network (CDN) such as Akamai or Limelight for mass distribution to
many client devices 415.
[0309] A similar level of efficiency can be gained when a CDN is used to
show Game Finder pages of top player groupings.
116
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0310] For major tournaments, a live celebrity announcer can be used to
provide commentary during certain matches. Although a large number of users
will be watching a major tournament, and relatively small number will be
playing
in the tournament. The audio from the celebrity announcer can be routed to the
app/game game servers 1521-1525 hosting the users playing in the tournament
and hosting any spectator mode copies of the game in the tournament, and the
audio can be overdubbed on top of the game audio. Video of a celebrity
announcer can be overlaid on the games, perhaps just on spectator views, as
well.
[03111 ACCELERATION OF WEB PAGE LOADING
[0312] The World Wide Web its primary transport protocol, Hypertext
Transfer Protocol (HTTP), were conceived and defined in an era where only
businesses had high speed Internet connections, and the consumers who were
online were using dialup modems or ISDN. At the time, the "gold standard" for
a
fast connection was a Ti line which provided 1.5Mbps data rate symmetrically
(i.e., with equal data rate in both directions).
[0313] Today, the situation is completely different. The average home
connection speed through DSL or cable modem connections in much of the
developed world has a far higher downstream data rate than a Ti line. In fact,
in
some parts of the world, fiber-to-the-curb is bringing data rates as high as
50 to
100Mbps to the home.
[0314] Unfortunately, HTTP was not architected (nor has it been
implemented) to effectively take advantage of these dramatic speed
improvements. A web site is a collection of files on a remote server. In very
simple terms, HTTP requests the first file, waits for the file to be
downloaded,
and then requests the second file, waits for the file to be downloaded, etc.
In fact,
HTTP allows for more than one "open connection", i.e., more than one file to
be
requested at a time, but because of agreed-upon standards (and a desire to
prevent
web servers from being overloaded) only very few open connections are
permitted. Moreover, because of the way Web pages are constructed, browsers
117
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
often are not aware of multiple simultaneous pages that could be available to
download immediately (i.e., only after parsing a page does it become apparent
that a new file, like an image, needs to be downloaded). Thus, files on
website
are essentially loaded one-by-one. And, because of the request-and-response
protocol used by HTTP, there is roughly (accessing typical web servers in the
US) a 100ms latency associated with each file that is loaded.
[0315] With relatively low speed connections, this does not introduce
much of a problem because the download time for the files themselves dominates
the waiting time for the web pages. But, as connection speeds grow, especially
with complex web pages, problems begin to arise.
[0316] In the example shown in Figure 24, a typical commercial website
is shown (this particular website was from a major athletic shoe brand). The
website has 54 files on it. The files include HTML, CSS, JPEG, PHP, JavaScript
and Flash files, and include video content. A total of 1.5MBytes must be
loaded
before the page is live (i.e., the user can click on it and begin to use it).
There are
a number of reasons for the large number of files. For one thing, it is a
complex
and sophisticated webpage, and for another, it is a webpage that is assembled
dynamically based on the information about the user accessing the page (e.g.,
what country the user is from, what language, whether the user has made
purchases before, etc.), and depending on all of these factors, different
files are
downloaded. Still, it is a very typical commercial web page.
[0317] Figure 24 shows the amount of time that elapses before the web
page is live as the connection speed grows. With a 1.5Mbps connection speed
2401, using a conventional web server with a convention web browser, it takes
13.5 seconds until the web page is live. With a 12Mbps connection speed 2402,
the load time is reduced to 6.5 seconds, or about twice as fast. But with a
96Mbps
connection speed 2403, the load time is only reduced to about 5.5 seconds. The
reason why is because at such a high download speed, the time to download the
files themselves is minimal, but the latency per file, roughly 100ms each,
still
118
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
remains, resulting in 54 files * 100ms = 5.4 seconds of latency. Thus, no
matter
how fast the connection is to the home, this web site will always take at
least 5.4
seconds until it is live. Another factor is the server-side queuing; every
HTTP
request is added in the back of the queue, so on a busy server this will have
a
significant impact because for every small item to get from the web server,
the
HTTP requests needs to wait for its turn.
[0318] One way to solve these issues is to discard or redefine HTTP. Or,
perhaps to get the website owner to better consolidate its files into a single
file
(e.g., in Adobe Flash format). But, as a practical matter, this company, as
well as
many others has a great deal of investment in their web site architecture.
Further,
while some homes have 12-100Mbps connections, the majority of homes still
have slower speeds, and HTTP does work well at slow speed.
[0319] One alternative is to host web browsers on app/game servers 1521-
1525, and host the files for the web servers on the RAID arrays 1511-1512 (or
potentially in RAM or on local storage on the app/game servers 1521-1525
hosting the web browsers. Because of the very fast interconnect through the
inbound routing 1502 (or to local storage), rather than have 100ms of latency
per
file using HTTP, there will be de minimis latency per file using HTTP. Then,
instead of having the user in her home accessing the web page through HTTP,
the
user can access the web page through client 415. Then, even with a 1.5Mbps
connection (because this web page does not require much bandwidth for its
video), the webpage will be live in less than 1 second per line 2400.
Essentially,
there will be no latency before the web browser running on an app/game server
1521-1525 is displaying a live page, and there will be no detectable latency
before the client 415 displays the video output from the web browser. As the
user
mouses around and/or types on the web page, the user's input information will
be
sent to the web browser running on the app/game server 1521-1525, and the web
browser will respond accordingly.
119
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0320] One disadvantage to this approach is if the compressor is
constantly transmitting video data, then bandwidth is used, even if the web
page
becomes static. This can be remedied by configuring the compressor to only
transmit data when (and if) the web page changes, and then, only transmit data
to
the parts of the page that change. While there are some web pages with
flashing
banners, etc. that are constantly changing, such web pages tend to be
annoying,
and usually web pages are static unless there is a reason for something to be
moving (e.g., a video clip). For such web pages, it is likely the case the
less data
will be transmitted using the hosting service 210 than a conventional web
server
because only the actual displayed images will be transmitted, no thin client
executable code, and no large objects that may never be viewed, such as
rollover
images.
[0321] Thus, using the hosting service 210 to host legacy web pages, web
page load times can be reduces to the point where opening a web page is like
changing channels on a television: the web page is live effectively instantly.
[0322] FACILITATING DEBUGGING OF GAMES AND APPLICATIONS
[0323] As mentioned previously, video games and applications with real-
time graphics are very complex applications and typically when they are
released
into the field they contain bugs. Although software developers will get
feedback
from users about bugs, and they may have some means to pass back machine
state after crashes, it is very difficult to identify exactly what has caused
a game
or real-time application to crash or to perform improperly.
[0324] When a game or application runs in the hosting service 210, the
video/audio output of the game or application is constantly recorded on a
delay
buffer 1515. Further, a watchdog process runs each app/game server 1521-1525
which reports regularly to the hosting service control system 401 that the
app/game server 1521-1525 is running smoothly. If the watchdog process fails
to
report in, then the server control system 401 will attempt to communicate with
the app/game server 1521-1525, and if successful, will collect whatever
machine
120
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
state is available. Whatever information is available, along with the
video/audio
recorded by the delay buffer 1515 will be sent to the software developer.
[0325] Thus, when the game or application software developer gets
notification of a crash from the hosting service 210, it gets a frame-by-frame
record of what led up to the crash. This information can be immensely valuable
in
tracking down bugs and fixing them.
[0326] Note also, that when an app/game server 1521-1525 crashes the
server is restarted at the most recent restartable point, and a message is
provided
to the user apologizing for the technical difficulty.
[0327] RESOURCE SHARING AND COST SAVINGS
[0328] The system shown in Figures 4a and 4b provide a variety of
benefits for both end users and game and application developers. For example,
typically, home and office client systems (e.g., PCs or game consoles) are
only in
use for a small percentage of the hours in a week. According to an October 5,
2006 press release by the Nielsen Entertainment "Active Gamer Benchmark
Study" (http://www.prnewswire.com/cgi-
bin/stories.pl?ACCT=104&STORY=/www/story/ 10-05-
2006/0004446115&EDATE=) active gamers spend on average 14 hours a week
playing on video game consoles and about 17 hours a week on handhelds. The
report also states that for all game playing activity (including console,
handheld
and PC game playing) Active Garners average 13 hours a week. Taking into
consideration the higher figure of console video game playing time, there are
24*7=168 hours in a week, that implies that in an active gamer's home, a video
game console is in use only 17/168=10% of the hours of a week. Or, 90% of the
time, the video game console is idle. Given the high cost of video game
consoles,
and the fact that manufacturers subsidize such devices, this is a very
inefficient
use of an expensive resource. PCs within businesses are also typically used
only
a fraction of the hours of the week, especially non-portable desktop PCs often
required for high-end applications such as Autodesk Maya. Although some
121
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
businesses operate at all hours and on holidays, and some PCs (e.g., portables
brought home for doing work in the evening) are used at all hours and
holidays,
most business activities tend to center around 9AM to 5PM, in a given
business'
time zone, from Monday to Friday, less holidays and break times (such as
lunch),
and since most PC usage occurs while the user is actively engaged with the PC,
it
follows that desktop PC utilization tends to follow these hours of operation.
If we
were to assume that PCs are utilized constantly from 9AM to 5PM, 5 days a
week, that would imply PCs are utilized 40/168=24% of the hours of the week.
High-performance desktop PCs are very expensive investments for businesses,
and this reflects a very low level of utilization. Schools that are teaching
on
desktop computers may use computers for an even smaller fraction of the week,
and although it varies depending upon the hours of teaching, most teaching
occurs during the daytime hours from Monday through Friday. So, in general,
PCs and video game consoles are utilized only a small fraction of the hours of
the
week.
[0329] Notably, because many people are working at businesses or at
school during the daytime hours of Monday through Friday on non-holidays,
these people generally are not playing video games during these hours, and so
when they do play video games it is generally during other hours, such as
evenings, weekends and on holidays.
[0330] Given the configuration of the hosting service shown in Figure 4a,
the usage patterns described in the above two paragraphs result in very
efficient
utilization of resources. Clearly, there is a limit to the number of users who
can be
served by the hosting service 210 at a given time, particularly if the users
are
requiring real-time responsiveness for complex applications like sophisticated
3D
video games. But, unlike a video game console in a home or a PC used by a
business, which typically sits idle most of the time, servers 402 can be re-
utilized
by different users at different times. For example, a high-performance server
402
with high performance dual CPUs and dual GPUs and a large quantity of RAM
122
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
can be utilized by a businesses and schools from 9AM to 5PM on non-holidays,
but be utilized by gamers playing a sophisticated video game in the evenings,
weekends and on holidays. Similarly, low-performance applications can be
utilized by businesses and schools on a low-performance server 402 with a
Celeron CPU, no GPU (or a very low-end GPU) and limited RAM during
business hours and a low-performance game can utilize a low-performance server
402 during non-business hours.
[03311 Further, with the hosting service arrangement described herein,
resources are shared efficiently among thousands, if not millions, of users.
In
general, online services only have a small percentage of their total user base
using
the service at a given time. If we consider the Nielsen video game usage
statistics
listed previously, it is easy to see why. If active gamers play console games
only
17 hours of a week, and if we assume that the peak usage time for game is
during
the typical non-work, non-business hours of evenings (5-12AM, 7*5 days=35
hours/week) and weekend (8AM- 12AM, 16*2=32 hours/week), then there are
35+32=65 peak hours a week for 17 hours of game play. The exact peak user load
on the system is difficult to estimate for many reasons: some users will play
during off-peak times, there may be certain day times when there are
clustering
peaks of users, the peak times can be affected by the type of game played
(e.g.,
children's games will likely be played earlier in the evening), etc. But,
given that
the average number of hours played by a gamer is far less than the number of
hours of the day when a gamer is likely to play a game, only a fraction of the
number of users of the hosting service 210 will be using it at a given time.
For the
sake of this analysis, we shall assume the peak load is 12.5%. Thus, only
12.5%
of the computing, compression and bandwidth resources are used at a given
time,
resulting in only 12.5% of the hardware cost to support a given user to play a
given level of performance game due to reuse of resources.
[0332] Moreover, given that some games and applications require more
computing power than others, resources may be allocated dynamically based on
123
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
the game being played or the applications executed by users. So, a user
selecting
a low-performance game or application will be allocated a low-performance
(less
expensive) server 402, and a user selecting a high-performance game or
applications will be allocated a high-performance (more expensive) server 402.
Indeed, a given game or application may have lower-performance and higher-
performance sections of the game or applications, and the user can be switched
from one server 402 to another server 402 between sections of the game or
application to keep the user running on the lowest-cost server 402 that meets
the
game or application's needs. Note that the RAID arrays 405, which will be far
faster than a single disk, will be available to even low-performance servers
402,
that will have the benefit of the faster disk transfer rates. So, the average
cost per
server 402 across all of the games being played or applications being used is
much less than the cost of the most expensive server 402 that plays the
highest
performance game or applications, yet even the low-performance servers 402,
will derive disk performance benefits from the RAID arrays 405.
[0333] Further, a server 402 in the hosting service 210 may be nothing
more than a PC motherboard without a disk or peripheral interfaces other than
a
network interface, and in time, may be integrated down to a single chip with
just
a fast network interface to the SAN 403. Also, RAID Arrays 405 likely will be
shared amongst far many more users than there are disks, so the disk cost per
active user will be far less than one disk drive. All of this equipment will
likely
reside in a rack in an environmentally-controlled server room environment. If
a
server 402 fails, it can be readily repaired or replaced at the hosting
service 210.
In contrast, a PC or game console in the home or office must be a sturdy,
standalone appliance that has to be able to survive reasonable wear and tear
from
being banged or dropped, requires a housing, has at least one disk drive, has
to
survive adverse environment conditions (e.g., being crammed into an overheated
AV cabinet with other gear), requires a service warranty, has to be packaged
and
shipped, and is sold by a retailer who will likely collect a retail margin.
Further, a
124
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
PC or game console must be configured to meet the peak performance of the most
computationally-intensive anticipated game or application to be used at some
point in the future, even though lower performance games or application (or
sections of games or applications) may be played most of the time. And, if the
PC
or console fails, it is an expensive and time-consuming process (adversely
impacting the manufacturer, user and software developer) to get it repaired.
[0334] Thus, given that the system shown in Figure 4a provides an
experience to the user comparable to that of a local computing resource, for a
user
in the home, office or school to experience a given level of computing
capability,
it is much less expensive to provide that computing capability through the
architecture shown in Figure 4a.
[0335] ELIMINATING THE NEED TO UPGRADE
[0336] Further, users no longer have to worry about upgrading PCs and/or
consoles to play new games or handle higher performance new applications. Any
game or applications on the hosting service 210, regardless of what type of
server
402 is required for that game or applications, is available to the user, and
all
games and applications run nearly instantly (i.e., loading rapidly from the
RAID
Arrays 405 or local storage on a servers 402) and properly with the latest
updates
and bug fixes (i.e., software developers will be able to choose an ideal
server
configuration for the server(s) 402 that run(s) a given game or application,
and
then configure the server(s) 402 with optimal drivers, and then over time, the
developers will be able to provide updates, bug fixes, etc. to all copies of
the
game or application in the hosting service 210 at once). Indeed, after the
user
starts using the hosting service 210, the user is likely to find that games
and
applications continue to provide a better experience (e.g., through updates
and/or
bug fixes) and it may be the case that a user discovers a year later that a
new
game or application is made available on the service 210 that is utilizing
computing technology (e.g., a higher-performance GPU) that did not even exist
a
year before, so it would have been impossible for the user to buy the
technology a
125
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
year before that would play the game or run the applications a year later.
Since
the computing resource that is playing the game or running the application is
invisible to the user (i.e., from the user's perspective the user is simply
selecting a
game or application that begins running nearly instantly-much as if the user
had
changed channels on a television), the user's hardware will have been
"upgraded"
without the user even being aware of the upgrade.
[0337] ELIMINATING THE NEED FOR BACKUPS
[0338] Another major problem for users in businesses, schools and homes
are backups. Information stored in a local PC or video game console (e.g., in
the
case of a console, a user's game achievements and ranking) can be lost if a
disk
fails, or if there is an inadvertent erasure. There are many applications
available
that provide manual or automatic backups for PCs, and game console state can
be
uploaded to an online server for backup, but local backups are typically
copied to
another local disk (or other non-volatile storage device) which has to be
stored
somewhere safe and organized, and backups to online services are often limited
because of the slow upstream speed available through typical low-cost Internet
connections. With the hosting service 210 of Figure 4a, the data that is
stored in
RAID arrays 405 can be configured using prior art RAID configuration
techniques well-known to those skilled in the art such that if a disk fails,
no data
will be lost, and a technician at the server center housing the failed disk
will be
notified, and then will replace the disk, which then will be automatically
updated
so that the RAID array is once again failure tolerant. Further, since all of
the disk
drives are near one another and with fast local networks between them through
the SAN 403 it is not difficult in a server center to arrange for all of the
disk
systems to be backed up on a regular basis to secondary storage, which can be
either stored at the server center or relocated offsite. From the point of
view of the
users of hosting service 210, their data is simply secure all the time, and
they
never have to think about backups.
126
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0339] ACCESS TO DEMOS
[0340] Users frequently want to try out games or applications before
buying them. As described previously, there are prior art means by which to
demo (the verb form of "demo" means to try out a demonstration version, which
is also called a "demo", but as a noun) games and applications, but each of
them
suffers from limitations and/or inconveniences. Using the hosting service 210,
it
is easy and convenient for users to try out demos. Indeed, all the user does
is
select the demo through a user interface (such as one described below) and try
out
the demo. The demo will load almost instantly onto a server 402 appropriate
for
the demo, and it will just run like any other game or application. Whether the
demo requires a very high performance server 402, or a low performance server
402, and no matter what type of home or office client 415 the user is using,
from
the point of view of the user, the demo will just work. The software publisher
of
either the game or application demo will be able to control exactly what demo
the
user is permitted to try out and for how long, and of course, the demo can
include
user interface elements that offer the user an opportunity to gain access to a
full
version of the game or application demonstrated.
[0341] Since demos are likely to be offered below cost or free of charge,
some users may try to use demos repeated (particularly game demos, which may
be fun to play repeatedly). The hosting service 210 can employ various
techniques to limit demo use for a given user. The most straightforward
approach
is to establish a user ID for each user and limit the number of times a given
user
ID is allowed to play a demo. A user, however, may set up multiple user IDs,
especially if they are free. One technique for addressing this problem is to
limit
the number of times a given client 415 is allowed to play a demo. If the
client is a
standalone device, then the device will have a serial number, and the hosting
service 210 can limit the number of times a demo can be accessed by a client
with
that serial number. If the client 415 is running as software on a PC or other
device, then a serial number can be assigned by the hosting service 210 and
127
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
stored on the PC and used to limit demo usage, but given that PCs can be
reprogrammed by users, and the serial number erased or changed, another option
is for the hosting service 210 to keep a record of the PC network adapter
Media
Access Control (MAC) address (and/or other machine specific identifiers such
as
hard-drive serial numbers, etc.) and limit demo usage to it. Given that the
MAC
addresses of network adapters can be changed, however, this is not a foolproof
method. Another approach is to limit the number of times a demo can be played
to a given IP address. Although IP addresses may be periodically reassigned by
cable modem and DSL providers, it does not happen in practice very frequently,
and if it can be determined (e.g., by contacting the ISP) that the IP is in a
block of
IP addresses for residential DSL or cable modem accesses, then a small number
of demo uses can typically be established for a given home. Also, there may be
multiple devices at a home behind a NAT router sharing the same IP address,
but
typically in a residential setting, there will be a limited number of such
devices.
If the IP address is in a block serving businesses, then a larger number of
demos
can be established for a business. But, in the end, a combination of all of
the
previously mentioned approaches is the best way to limit the number of demos
on
PCs. Although there may be no foolproof way that a determined and technically
adept user can be limited in the number of demos played repeatedly, creating a
large number of barriers can create a sufficient deterrent such that it's not
worth
the trouble most PC users to abuse the demo system, and rather they use the
demos as they were intended to try out new games and applications.
[0342] BENEFITS TO SCHOOLS, BUSINESSES AND OTHER INSTITUTIONS
[0343] Significant benefits accrue particularly to businesses, schools and
other institutions that utilize the system shown in Figure 4a. Businesses and
schools have substantial costs associated with installing, maintaining and
upgrading PCs, particularly when it comes to PCs for running high-performance
applications, such a Maya. As stated previously, PCs are generally utilized
only a
fraction of the hours of the week, and as in the home, the cost of PC with a
given
128
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
level of performance capability is far higher in an office or school
environment
than in a server center environment.
[0344] In the case of larger businesses or schools (e.g., large universities),
it may be practical for the IT departments of such entities to set up server
centers
and maintain computers that are remotely accessed via LAN-grade connections.
A number of solutions exist for remote access of computers over a LAN or
through a private high bandwidth connection between offices. For example, with
Microsoft's Windows Terminal Server, or through virtual network computing
applications like VNC, from Rea1VNC, Ltd., or through thin client means from
Sun Microsystems, users can gain remote access to PCs or servers, with a range
of quality in graphics response time and user experience. Further, such self-
managed server centers are typically dedicated for a single business or school
and
as such, are unable to take advantage of the overlap of usage that is possible
when
disparate applications (e.g., entertainment and business applications) utilize
the
same computing resources at different times of the week. So, many businesses
and schools lack the scale, resources or expertise to set up a server center
on their
own that has a LAN-speed network connection to each user. Indeed, a large
percentage of schools and businesses have the same Internet connections (e.g.,
DSL, cable modems) as homes.
[0345] Yet such organizations may still have the need for very high-
performance computing, either on a regular basis or on a periodic basis. For
example, a small architectural firm may have only a small number of
architects,
with relatively modest computing needs when doing design work, but it may
require very high-performance 3D computing periodically (e.g., when creating a
3D fly-through of a new architectural design for a client). The system shown
in
Figure 4a is extremely well suited for such organizations. The organizations
need
nothing more than the same sort of network connection that are offered to
homes
(e.g., DSL, cable modems) and are typically very inexpensive. They can either
utilize inexpensive PCs as the client 415 or dispense with PCs altogether and
129
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
utilize inexpensive dedicated devices which simply implement the control
signal
logic 413 and low-latency video decompression 412. These features are
particularly attractive for schools that may have problems with theft of PCs
or
damage to the delicate components within PCs.
[0346] Such an arrangement solves a number of problems for such
organizations (and many of these advantages are also shared by home users
doing
general-purpose computing). For one, the operating cost (which ultimately must
be passed back in some form to the users in order to have a viable business)
can
be much lower because (a) the computing resources are shared with other
applications that have different peak usage times during the week, (b) the
organizations can gain access to (and incur the cost of) high performance
computing resources only when needed, (c) the organizations do not have to
provide resources for backing up or otherwise maintaining the high performance
computing resources.
[0347] ELIMINATION OF PIRACY
[0348] In addition, games, applications, interactive movies, etc, can no
longer be pirated as they are today. Because game is executed at the service
center, users are not provided with access to the underlying program code, so
there is nothing to pirate. Even if a user were to copy the source code, the
user
would not be able to execute the code on a standard game console or home
computer. This opens up markets in places of the world such as China, where
standard video gaming is not made available. The re-sale of used games is also
not possible.
[0349] For game developers, there are fewer market discontinuities as is
the case today. The hosting service 210 can be gradually updated over time as
gaming requirements change, in contrast to the current situation where a
completely new generation of technology forces users and developers to upgrade
and the game developer is dependent on the timely delivery of the hardware
platform.
130
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0350] STREAMING INTERACTIVE VIDEO
[03511 The above descriptions provide a wide range of applications
enabled by the novel underlying concept of general Internet-based, low-latency
streaming interactive video (which implicitly includes audio together with the
video as well, as used herein). Prior art systems that have provided streaming
video through the Internet only have enabled applications which can be
implemented with high latency interactions. For example, basic playback
controls
for linear video (e.g. pause, rewind, fast forward) work adequately with high
latency, and it is possible to select among linear video feeds. And, as stated
previously, the nature of some video games allow them to be played with high
latency. But the high latency (or low compression ratio) of prior art
approaches
for streaming video have severely limited the potential applications of
streaming
video or narrowed their deployments to specialized network environments, and
even in such environments, prior art techniques introduce substantial burdens
on
the networks. The technology described herein opens the door for the wide
range
of applications possible with low-latency streaming interactive video through
the
Internet, particularly those enabled through consumer-grade Internet
connections.
[0352] Indeed, with client devices as small as client 465 of Figure 4c
sufficient to provide an enhanced user experience with an effectively
arbitrary
amount of computing power, arbitrary amount of fast storage, and extremely
fast
networking amongst powerful servers, it enables a new era of computing.
Further,
because the bandwidth requirements do not grow as the computing power of the
system grows (i.e., because the bandwidth requirements are only tied to
display
resolution, quality and frame rate), once broadband Internet connectivity is
ubiquitous (e.g., through widespread low-latency wireless coverage), reliable,
and
of sufficiently high bandwidth to meet the needs of the display devices 422 of
all
users, the question will be whether thick clients(such as PCs or mobile phones
running Windows, Linux, OSX, etc.,) or even thin clients (such as Adobe Flash
or Java) are necessary for typical consumer and business applications.
131
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0353] The advent of streaming interactive video results in a rethinking of
assumptions about the structure of computing architectures. An example of this
is
the hosting service 210 server center embodiment shown in Figure 15. The video
path for delay buffer and/or group video 1550 is a feedback loop where the
multicasted streaming interactive video output of the app/game servers 1521-
1525 is fed back into the app/game servers 1521-1525 either in real-time via
path
1552 or after a selectable delay via path 1551. This enables a wide range of
practical applications (e.g. such as those illustrated in Figures 16, 17 and
20) that
would be either impossible or infeasible through prior art server or local
computing architectures. But, as a more general architectural feature, what
feedback loop 1550 provides is recursion at the streaming interactive video
level,
since video can be looped back indefinitely as the application requires it.
This
enables a wide range of application possibilities never available before.
[0354] Another key architectural feature is that the video streams are
unidirectional UDP streams. This enables effectively an arbitrary degree of
multicasting of streaming interactive video (in contrast, two-way streams,
such as
TCP/IP streams, would create increasingly more traffic logjams on the networks
from the back-and-forth communications as the number of users increased).
Multicasting is an important capability within the server center because it
allows
the system to be responsive to the growing needs of Internet users (and indeed
of
the world's population) to communicate on a one-to-many, or even a many-to-
many basis. Again, the examples discussed herein, such as Figure 16 which
illustrates the use of both streaming interactive video recursion and
multicasting
are just the tip of a very large iceberg of possibilities.
[0355] In one embodiment, the various functional modules illustrated
herein and the associated steps may be performed by specific hardware
components that contain hardwired logic for performing the steps, such as an
application-specific integrated circuit ("ASIC") or by any combination of
programmed computer components and custom hardware components.
132
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
[0356] In one embodiment, the modules may be implemented on a
programmable digital signal processor ("DSP") such as a Texas Instruments'
TMS320x architecture (e.g., a TMS320C6000, TMS320C5000, ... etc). Various
different DSPs may be used while still complying with these underlying
principles.
[0357] Embodiments may include various steps as set forth above. The
steps may be embodied in machine-executable instructions which cause a
general-purpose or special-purpose processor to perform certain steps. Various
elements which are not relevant to these underlying principles such as
computer
memory, hard drive, input devices, have been left out of the figures to avoid
obscuring the pertinent aspects.
[0358] Elements of the disclosed subject matter may also be provided as a
machine-readable medium for storing the machine-executable instructions. The
machine-readable medium may include, but is not limited to, flash memory,
optical disks, CD-ROMs, DVD ROMs, RAMs, EPROMs, EEPROMs, magnetic
or optical cards, propagation media or other type of machine-readable media
suitable for storing electronic instructions. For example, the present
invention
may be downloaded as a computer program which may be transferred from a
remote computer (e.g., a server) to a requesting computer (e.g., a client) by
way
of data signals embodied in a carrier wave or other propagation medium via a
communication link (e.g., a modem or network connection).
[0359] It should also be understood that elements of the disclosed subject
matter may also be provided as a computer program product which may include a
machine-readable medium having stored thereon instructions which may be used
to program a computer (e.g., a processor or other electronic device) to
perform a
sequence of operations. Alternatively, the operations may be performed by a
combination of hardware and software. The machine-readable medium may
include, but is not limited to, floppy diskettes, optical disks, CD-ROMs, and
magneto-optical disks, ROMs, RAMs, EPROMs, EEPROMs, magnet or optical
133
CA 02707704 2010-06-02
WO 2009/073826 PCT/US2008/085601
cards, propagation media or other type of media/machine-readable medium
suitable for storing electronic instructions. For example, elements of the
disclosed
subject matter may be downloaded as a computer program product, wherein the
program may be transferred from a remote computer or electronic device to a
requesting process by way of data signals embodied in a carrier wave or other
propagation medium via a communication link (e.g., a modem or network
connection).
[0360] Additionally, although the disclosed subject matter has been
described in conjunction with specific embodiments, numerous modifications and
alterations are well within the scope of the present disclosure. Accordingly,
the
specification and drawings are to be regarded in an illustrative rather than a
restrictive sense.
134
