Note: Descriptions are shown in the official language in which they were submitted.
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PORTABLE MOVING PICTURE RECORDING DEVICE
INCLUDING SWITCHING CONTROL FOR
MULTIPLE DATA FLOW CONFIGURATIONS
Field of the Invention
This invention relates to moving picture recording devices and processes. More
particularly, the invention relates to controlling data flow using switches in
a moving picture
recording device to provide multiple functions in a portable recorder.
lU
Background of the Invention
Present day video recorders are typically a combination of a video camera with
a video
tape recorder which are constructed so as to be portable. They are often
called camcorders or
video tape recorders (VTR). For the purposes of this application, they are
referred to as video
~ 5 tape recorders. Present day portable video tape recorders use a video
tape, usually contained
within a cassette, as the recording medium. Recording is done in numerous
formats, including
analog BETA and VHS format, and the digital D1 format. A major disadvantage of
video tape
recorders is that video tape allows only linear access to a given point on the
video tape. That is,
if the tape has just finished recording, in order to access the beginning of a
recorded session
2o located at the beginning of the tape, the tape must be rewound.
The problem of linear access to video tape recordings is most obvious in the
field of
broadcast television news. Typically, a reporting crew goes to a news location
with a video tape
recorder and record an event. Upon completion of recording. the tape is
rewound and then
played back and transmitted, for example via satellite or microwave link, to a
base station a
25 studio facility. At the base station, the information then can be edited
into a final news program.
Editing of moving pictures is commonly done digitally, using a non-linear
computer-based editing system such as the Avid/1 Media Composer or the
NewsCutter, both
available from Avid Technology, Inc. of Tewksbury, Massachusetts. Such a
system typically
digitizes, or, converts analog video signals into a digital, computer-readable
format. Even if the
3o video signal is from a digital video tape, linear access to information on
the tape still presents the
same problems. Tape recording, transmission and digitization are usually
performed unless there
is an actual live connection from the camera to the base station. Because of
the amount of time
required for rewinding, playback and transmission of recorded information from
a video tape,
there is typically a half hour delay between the completion of recording of an
event and the time
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an edited version of the recorded event actually can be broadcast by the base
station. This delay
is a significant competitive problem in~broadcast news where the time to air
is very important as
stations strive to produce "up to the minute" news coverage and broadcast.
Today, electronic still cameras exist which record a still image on magnetic
medium.
such as a floppy disk. Such a camera is described in U.S. Patent No.
5,084,775, issued January
28, 1991, and assigned to Sony Corporation. However, the camera described in
that patent
records still images only, not full motion video images. In addition. computer
video capture
systems exist. such as the NuVista video capture card available frOln
RasterOps/Truevision. Inc.
Such systems, however, have not been combined with a video camera reduced to
the portable
~ o form to perform live digital capture directly from a camera without
intervening tape.
Additionally, it has been recently suggested by some skilled in the field of
moving
picture recording that numerous problems with a non-linear digital moving
picture recorder are
insurmountable. In particular, it has been suggested that there is a large
image quality trade-off
with increased recording time capability. Additionally, it has been suggested
that, using
t i disk-based media, a little shake of the camera would cause a disk crash.
Finally. it has been
suggested that the disk media is substantially costlier than tape.
Additionally, while still picture editing is available in some digital still
video cameras,
such as described in U.S. Patent No. 5,301,026, such editing is significantly
simpler than a
full-motion video editing system and thus, such a still camera is not capable
of recording or
20 editing moving pictures.
Additionally. it is known that in many television stations there are a variety
of
switching capabilities to allo~r multiple sources of information to be fed to
a single output
channel. These sources are generally locked to and synchronized with the
output channel
frequenc~~. Switching is performed between vertical time intervals, i.e.,
between frames, using a
25 vertical time interval switch (VTIS). However, in a camera, there are
typically only two sources
of output, either live images or playback from tape, which are designed to be
preselected by a
user during playback but do not incorporate a VTIS.
Summary of the Invention
30 The present invention combines editing capability typically found only in a
production
studio along with switching capabilities typically found only in a television
station, in a portable
moving picture recorder that records on computer-readable and writable random
access recording
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media, such as a magnetic or optical disk. With such a
combination, the capability and functionality of a full
television broadcast news studio is provided on the shoulder
of an individual in a portable camera.
In accordance with one aspect of the present
invention, there is provided a digital motion video
recorder, comprising: a housing sized to be portable by an
individual; a decoder, mounted in the housing, for receiving
a broadcast television quality full motion video signal and
for converting the broadcast television quality full motion
video signal into a sequence of digital still images; a
digital computer-readable and veritable random-access medium
mounted in the housing and connected both to receive and
store and to retrieve and playback the sequence of digital
still images in a computer-readable file format; an encoder,
having an input for receiving a sequence of digital still
images, for generating as an output a broadcast television
quality full motion video signal; a vertical time interval
switch having a first input receiving the sequence of
digital still images from the decoder and a second input
receiving the sequence of digital still images from the
digital computer-readable and veritable random-access medium,
and an output connected to the input of the encoder; and an
interface responsive to a user input to cause the switch to
provide one of the first and second inputs to the input of
the encoder.
In accordance with a second aspect of the present
invention, there is provided a digital motion picture
recorder, comprising: a housing sized to be portable for
use by an individual; a camera mounted in the housing having
an output for providing a full motion video signal; a
decoder, mounted in the housing, for receiving the full
motion video signal from the camera and for converting the
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full motion video signal into a sequence of digital still
images; a digital, computer-readable and writable random-
access medium mounted in the housing, and connected to
receive and store the sequence of digital still images from
the decoder in a computer-readable file format and to
provide digital still images stored thereon; means, in the
housing, for enabling the individual to capture digital
still images from the decoder into a plurality of data files
on the digital, computer-readable and writable random-access
medium, wherein each of the plurality of data files stores a
sequence of digital still images; an encoder mounted in the
housing and having an input for receiving a sequence of
digital still images, for generating as an output a full
motion video signal; a switch mounted in the housing and
having a first input for receiving digital still images from
the decoder and a second input for receiving digital still
images from the digital, computer-readable and writable
random-access medium, and an output connected to the input
of the encoder; an interface on the housing for causing the
switch to provide one of the first and second inputs as the
sequence of digital still images to the input of the
encoder; means, in the housing, for enabling the individual
to specify a sequence of segments of the plurality of data
files stored on the digital, computer-readable and writable
random-access medium; and means, in the housing, for
enabling the individual to initiate playback of full motion
video through the switch and the encoder using the digital
still images from the plurality of data files stored on the
digital, computer-readable and writable random-access medium
according to the specified sequence of segments of the
plurality of data files.
In accordance with a third aspect of the present
invention, there is provided a digital video recording
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device, comprising: a portable housing; a camera mounted in
the portable housing having an output providing a video
signal; a decoder mounted in the portable housing having an
input connected to the output of the camera and an output
providing digital video information as a sequence of digital
still images; a random-access, computer-readable and
writable medium mounted in the portable housing and for
storing digital video information from the decoder as a
sequence of digital still images in a computer-readable file
format and for providing digital video information stored
thereon; means, in the portable housing, for enabling a user
to capture sequences of digital still images from the
decoder into a plurality of data files on the random-access,
computer-readable and writable medium, wherein each of the
plurality of data files stores a sequence of digital still
images; an encoder mounted in the portable housing and
having an input for receiving a sequence of digital still
images and having an output for providing an output video
signal from the received sequence of digital still images; a
switch mounted in the portable housing having a first input
for receiving the sequence of digital still images from the
decoder and a second input for receiving the sequence of
digital still images from the random-access,
computer-readable and writable medium, and an output
connected to provide one of the received sequences of
digital still images to the input of the encoder; an
interface on the portable housing for causing the switch to
provide one of the first and second inputs to the input of
the encoder; and means, in the portable housing, for
enabling the user to specify a sequence of segments of the
plurality of data files stored on the random-access,
computer-readable and writable medium; and means, in the
portable housing, for enabling the user to initiate playback
of full motion video by the encoder by providing the digital
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still images from the plurality of data files stored on the
random-access, computer-readable and writable medium through
the switch according to the specified sequence of segments
of the plurality of data files.
In accordance with a fourth aspect of the present
invention, there is provided a digital video recording
device, comprising: a portable housing; a camera mounted in
the portable housing having an output for providing a full
motion video signal; a digital, computer-readable and
writable random access medium mounted in the portable
housing; means, in the portable housing, for enabling a user
to capture digital video information corresponding to the
full motion video signal into a plurality of data files in a
computer readable file format on the digital, computer-
readable and writable random-access medium; an encoder
mounted in the portable housing and having a first input for
receiving digital video information from files stored on the
digital computer-readable and writable random-access medium,
a second input for receiving digital video information
corresponding to the full motion video signal from the
camera and an output providing a video signal according to
the first or second input; means in the portable housing for
causing the encoder to select between the first and second
inputs; and means in the portable housing for enabling the
user to specify a sequence of segments of the plurality of
data files stored on the digital, computer-readable and
writable random-access medium; and means in the portable
housing for enabling the user to initiate playback of full
motion video by the encoder by providing the digital video
information from the plurality of data files stored on the
digital, computer-readable and writable random-access medium
to the first input of the encoder according to the specified
sequence of segments of the plurality of data files.
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In accordance with a fifth aspect of the present
invention, there is provided a digital video recording
device, comprising, in a portable housing: a camera for
providing a full motion video signal; means for storing
data; means for enabling a user to capture digital video
information corresponding to the full motion video signal
into a plurality of data files in a computer readable file
format on the means for storing; an encoder having a first
input for receiving stored digital video information from
the means for storing and a second input for receiving
digital video information corresponding to the full motion
video signal, and an output for providing a video signal
according to either the first or second input; means for
causing the encoder to select between the first and second
inputs; and means for enabling the user to specify a
sequence of segments of the plurality of data files stored
on the means for storing; and means for enabling the user to
initiate playback of full motion video by the encoder by
providing the digital video information from the plurality
of files stored on the means for storing to the first input
of the encoder according to the specified sequence of
segments of the plurality of data files.
In accordance with a sixth aspect of the present
invention, there is provided a digital video recording
device, comprising: a portable housing; a camera attached
to the portable housing and having an output providing live
digital video information; a display mounted on the portable
housing; a random access, computer-readable and writable
medium mounted within the portable housing; means, in the
portable housing, for enabling a user to capture digital
video information from the camera into a plurality of data
files in a computer readable file format on the random
access, computer-readable and writable medium; a first
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encoder mounted within the portable housing having an input
for receiving digital video information and an output for
providing output video information; a second encoder mounted
within the portable housing having an input for receiving
digital video information and an output for providing an
output video signal to the display; a first switch mounted
within the portable housing and having a first input for
receiving live digital video information from the camera and
a second input for receiving recorded digital video
information from the random access computer-readable and
writable medium, and an output connected to provide the
digital video information to the input of the first encoder;
a second switch mounted within the portable housing and
having a first input for receiving live digital video
information from the camera and a second input for receiving
recorded digital video information from the random access
computer-readable and writable medium, and an output
connected to provide the digital video information to the
input of the second encoder; means for enabling the user to
specify a sequence of segments of the plurality of data
files stored on the random access, computer-readable and
writable medium; means for enabling the user to initiate
playback of full motion video by the first encoder by
providing the digital video information from the plurality
of files stored on the random access, computer readable and
writable medium through the first switch according to the
specified sequence of segments of the plurality of data
files, including means for controlling the first switch; and
means for enabling the user to initiate playback of full
motion video by the second encoder by providing the digital
video information from the plurality of files stored on the
random access, computer readable and writable medium through
the second switch, according to the specified sequence of
~
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segments of the plurality of data files, including means for
controlling the second switch.
In accordance with a seventh aspect of the present
invention, there is provided a digital video recording
device, comprising: a portable housing; a camera mounted in
the portable housing having an output for providing a full
motion video signal; a digital, computer-readable and
veritable random access medium mounted in the portable
housing; means, in the portable housing, for enabling a user
to capture digital video information corresponding to the
full motion video signal into a plurality of data files in a
computer readable file format on the digital, computer-
readable and veritable random-access medium; an encoder
mounted in the portable housing and having a first input for
receiving digital video information from files stored on the
digital computer-readable and veritable random-access medium,
a second input for receiving digital video information
corresponding to the full motion video signal from the
camera and an output providing a video signal according to
the first or second input; means in the portable housing for
causing the encoder to select between the first and second
inputs; and means in the portable housing for enabling the
user to specify a list of portions of the plurality of data
files stored on the digital, computer-readable and veritable
random-access medium; and means in the portable housing for
enabling the user to initiate playback of full motion video
by the encoder as a contiguous output signal by providing
the digital video information from the plurality of data
files stored on the digital, computer-readable and veritable
random-access medium to the first input of the encoder
according to the specified list of portions of the plurality
of data files.
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An embodiment of the invention is an electrical circuit which processes motion
video and
provides switching capability between a number of sources. In one embodiment,
the circuit has
an output switch which provides an output video signal selected from one of a
received video
signal or a video signal generated from digital video information stored on a
recording medium.
This embodiment may have two encoders for generating a video signal and a
switch between
their outputs, or a single encoder have a switch at its input. In another
embodiment, the output
~ o video signal is selected from one of two received video sources, including
a live camera. In
another embodiment. two outputs are provided. Either or both of these outputs
may include a
switch to select one from any combination of one or more received sources and
a recorded
source. In another embodiment. the recording medium may be selected to record
a selected
received video signal.
In a particular embodiment of the invention, each of the received sources and
the
recorded video information directed through the electrical circuit on one or
more pixel buses
under flow control by a central processing unit. By having one pixel bus for
received video data
and a second pixel bus for recorded video data and outputs which select from
one of the pixel
buses, it is possible to view received data and recorded data simultaneously.
2o Another embodiment of the invention is a moving picture camera which
provides an output video
signal, typically an analog composite video signal. to a decoder. The decoder
decodes the output
video signal into a sequence of digital still images. The digital video
information from the
decoder is connected to an input of an encoder. The encoder generates a
broadcast video signal
output from the digital video information. This video signal from the camera
is also applied to
an analog-to-digital converter, of which a digital output is applied to a
second decoder which
generates component information. The output of this second decoder is applied
to an input of the
encoder. Additionally, the output of the second decoder is connected to a
record and playback
circuit, which records a digital video information stream onto a recording
medium or plays back
information from the recording medium. The record and playback circuit is also
connected. in its
playback mode, to the input of the encoder. A second encoder is also provided
which has an
input connected to the output of the record and playback circuit (in playback)
and to the output of
the two decoders. In an embodiment with a set of switches in the decoder to
enable selection of
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an input signal source, the decoders can be connected to receive video
information from either
the camera or an external video source. Thus, the broadcast output encoder can
either playback
live information or previously recorded information. The second encoder can
either playback
information coming through the decoder or from the record and playback
circuit.
a An embodiment of the various aspects of the invention includes an editing
system
which allows a list of portions of the recorded media to be played. Using a
random-access
recording medium, real time playback of edited clips in an edited sequence is
provided directly
on the camera. Additionally, this playback list may include live sequences and
thus provides on
the camera a broadcast output that switches between live images and
prerecorded clips which
o may have been edited. This allows a contiguous output video signal to be
generated from these
multiple sources within the camera.
More particularly, with the switching arrangement provided. multiple functions
and
combinations and sequences of these functions can be obtained. For example,
while the camera
is being played live on the air, material recorded on the disk may be
previewed through the view
l5 finder, and/or edited. Live material may also be recorded. Additionally.
external video may be
previewed or recorded. While material recorded on the disk is being played
back to air, it may
be simultaneously viewed in the view finder or monitor. Additionally, live
video from the
camera or external video may also be directed to the view finder. While the
camera is recording,
either the camera or external video may be sent to live broadcast output.
Additionally, when
20 external video is being broadcast directly to air, material on the disk may
be previewed and
edited, video information from the camera may be previewed or recorded, and
finally the
external video information may also be recorded. Finally. the controller may
be programmed to
sequence among any of these modes.
In an embodiment providing an Ethernet or other computer-based communication
25 connection, all of these functional capabilities can be provided under
remote control.
In embodiments of the various aspects of the invention, a digital, computer-
readable
and veritable random access recording medium, such as a magnetic or optical
disk, is combined
with a motion picture camera device. In one embodiment, by providing a smaller
sized disk
drive, e.g., 2'/2 inches in diameter, and shock and vibration isolation
packaging, the risk of
3o damage or disk failure is significantly reduced. Broadcast quality video is
provided by a
compressed stream of digital motion picture information at rates of four
megabytes per second.
Another aspect of the invention, which is also useful .in combination with the
other
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various aspects of the invention. is a switching system for receiving,
recording and playing back
recorded audio data. Similar to the video switching, an output for each audio
channel selects
between one of received audio data and recorded audio data. It is also
possible to output and
record received audio data simultaneously. and simultaneously with video. An
embodiment of
- 5 the invention includes an editing system that allows for selection and
editing of audio clips, as
with the embodiment of the editing system for video clips. An audio channel
may also include
mixing capabilities.
In the various aspects of the invention, the recording medium may be a media
data
buffer and primary media storage, such as a disk drive. A processor controls
data flow into and
t o out of the media data buffer to and from any output. Video information may
be stored on and
read from the primary media storage using a form of demand-based flow control,
since such
digital video information does not require global synchronization. The video
data written to and
read from the primary storage into a media buffer is transferred to the
outputs or from the inputs
as the video data is needed. The video data may be stored as a data file
according to an operating
15 system executed by a central processing unit.
By providing a portable video recorder which records directly onto digital
computer
readable and veritable random access (i.e., non-linear) medium, there is no
longer a significant
delay due to rewinding of the tape or for digitization of video tape for
editing purposes. By
further combining the advantages of non-linear recording and non-linear
editing with non-linear
2o broadcasting system and switching control, the time from videography to
broadcast of an edited
news event is drastically reduced. This reduction of the time from videography
to broadcast
provides a significant competitive advantage for broadcast news stations.
Brief Description of the Drawing
25 In the drawing,
Fig. 1 is a left side view of a digital motion picture recorder affixed to a
video camera in
' accordance with the present invention;
Fig. 2 is a right side view of the digital motion picture recorder of Fig. 1;
Fig. 3 is a block diagram of the electronic circuitry which processes the
camera and
3o audio signals into media files for storage on a computer readable and
veritable random access
storage medium;
Fig. 4 is a more detailed block diagram of the block diagram of Fig. 3,
illustrating
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switching paths;
Fig. ~ is a more detailed block diagram of the circuit illustrated in Fig. 4,
Fig. 6 illustrates audio signal paths; and ,
Fig. 7 illustrates synchronization circuitry for the audio and video paths.
Detailed Description
The present invention will be more completely understood through the following
detailed description which should be read 111 COll~llllctlon Wlth the attached
drawing in which
similar reference numbers indicate similar structures.
t U A general description of the moving picture recording device is first
provided in
connection with Figs. 1-3. Details concerning switching capabilities are
described 111 more detail
below in connection with Figs. 4-7.
Fig. 1 shows a video camera/recorder 20 which includes a combination of a
video
camera ?? and a video recorder 24. The camera may be one of many types of
video cameras. and
t s may be, for example, either the HL-~7 camera made by Ikegami Corporation
of Japan. or the
"400." camera made by the Sony Corporation of Japan. The video camera/recorder
20 also
typically has a handle 26 and shoulder support 28. On the video recorder 24 of
the device,
typically a display 30 is used to provide the user status and other pertinent
information to be
detailed below. The camera, electronic circuitry (such as described below in
connection with
20 Figs. 3-4) and recording medium may be in one piece, such that the camera
22 and recorder 24
are integrated, or may be in two pieces such that the camera 22 and recorder
24 are separable
from each other. Many tape-based recorders used for news reporting are in such
a two-part form,
and often take the shape as shown in Japanese utility model 63-9907, also
referred to as
56-134889, or Japanese patent 61-187165.
25 The output of the video camera is generally an analog video signal.
Presently known
cameras available from Ikegami have a 79-line bus for the purposes of
communicating with a
recorder, whereas Sony cameras use a 52-line bus. The recorder provides a
physical and
electrical connections to interface with a standard bus such as the Ikegami,
Sony or other
standard bus, so that the motion picture recorder receives the output of the
camera as if the
30 recorder were a videocassette recorder. The motion picture recorder also
includes, using
techniques well known to those skilled in the art. electrical contacts and
connections (not shown)
to turn the camera on and off, initiate recording, etc.
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Fig. 2 shows the opposite side view of the camera shown in Fig. 1. On this
side of the
camera is found the recording media compartment 42 which is accessed via a
door 43. External
connections, such as 48 and 49, provide external video output, ETHERNET or
other kinds of
connections. The door 43 has a hinged section 44 and a handle 45 so that the
door may be
a opened. The compartment 42 is an opening within the recorder and includes a
connector (not
shown) at the bottom of the compartment. Which receives a recording media
package which
connects to connector to provide electronic connection to the remainder of the
circuitry of the
recorder. The media package and connection to the recorder are described in
more detail in U.S.
Patent Serial No. 5,999,406.
io
Having now described a general mechanical structure of an embodiment of the
moving
picture recorder. the electronic circuitry for processing the moving pictures
will now be
described. The output of the video camera 22, which is generally an analog
signal. is provided to
the digitizing electronic circuitry such as shown in Figs. 3-9. Referring to
Fig. 3. such circuitry
~ 5 generally includes a digitizer 35, compression circuitry 37. and a
computer-readable and writable
random-access recording medium 39, such as a disk drive. as described above.
While the
digitizer 35 is used for those video cameras which produce an analog output
signal. the digitizer
would be unnecessary if the output of the video camera were to be digital. In
some prior art
systems, the image captured by the camera 31 of Fig. 1 is impressed upon a
charge coupled
20 device (CCD), well known to those skilled in the art. The CCD produces an
electrical signal,
which is then processed (either digitally or with analog circuitry) to create
an analog video signal
so that those signals may be passed to a conventional analog video cassette
recorder. A digital
video signal or a digital video information stream may be input directly to
the compression
circuitry 37 of Fig. 3. eliminating the digital-to-analog and analog-to-
digital conversions
25 associated with prior art devices from the circuitry within the camera 31.
However. to interface a recorder with presently existing analog output video
cameras.
the digitizer 35 is used. The digitizer may comprise a number of analog to
digital (A/D)
converters. These converters, well known to those skilled in the art, may
accept the output of the
analog video camera, and may comprise on A/D converter for each component Y.
Cr and Cb
3o signal from the video camera. Analog composite video may also be decoded
into digital video
data. Digital video may also be processed and synchronization signals may be
removed to
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provide digital video information. A 4:2:2 format is typically used. but 4:1:1
and 4:4:4 formats
may also be used. Other color formats may be used such as CMYK, HSI and RGB in
8, 16 or 32
bits formats. However, the Y, Cr, Cb format is preferable for use with the
well known Joint
Photographer's Expert Group (JPEG) compression standard, which may be used in
this moving
picture recorder. Other compression standards, well known in the art, such as
MPEG, may also
be suitable for use in the present invention. The video may also remain
uncompressed.
However, JPEG compression is useful for editing because it does not rely on
differences between
adjacent frames or fields, but instead each frame or field is self contained.
Digitizing and
compression/decompression circuitry is described in U.S Patents 5,355,450,
x,045,940 and
to published Patent Cooperation Treaty (PCT) applications W093/12481 and
W093/12613.
Audio signals are also processed and recorded. The audio signal is digitized
from a
microphone. Digitization is unnecessary if a digital audio source is used.
Audio is generally not
compressed.
One difference between the systems described in the above patents and
published
applications and an embodiment of the present invention is that this
embodiment of the present
invention does not require a frame grabber or frame buffer. The frame buffer
is eliminated to
reduce power consumption, which is desirable with a portable, battery-powered
system.. Its
removal is possible by using a high throughput compression circuit such as the
ZR36050 and
ZR36015 JPEG compression circuits, available from Zoran of Santa Clara,
California. These
2o circuits provide full 60 field per second uncompressed data rates for 720 X
480 digital still
images, which provides CCIR601 compliant broadcast quality images. Due to the
high
throughput compression circuit, the compression circuitry of this embodiment
does not require
any stalling or metering mechanism for delaying processing of data through
this pipeline. Other
circuits are available for JPEG compression, such as from LSI Logic.
In order to maintain correct color of the captured imOges from the video
camera, the
signals from the camera may be calibrated to match well known and established
SMPTE digital
video color standards. In the absence of such calibration, the compression
circuitry of the one
embodiment of the invention, based on the well known and established JPEG
compression
standard, may create errors because JPEG compression relies on frequencies
derived from the
3o colors present in the signal. Calibration is done automatically in response
to actuation of a
calibration selection switch 33 on the video recorder of Fig. 1. Such
calibration typically is
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performed both periodically during use and whenever a camera is associated
with new
calibration and digitizing circuitry.
Calibration is performed by causing the camera to generate a reference signal.
A
commonly-used reference signal is known as "color bars" or a "test pattern."
The test pattern for
any given camera is in a predetermined format and is typically generated by
the camera circuitry
in a known manner. Using this format, the overall signal level of the color
bar signal is
determined by the recorder, and thus the values output by the camera and, by
inference. the CCD
device are determined. These values are then mapped, using well known mapping
technic]ues, to
the SMPTE standard for digital color representations, of which an indication
is stored in the
recorder. More precisely, the A/D converters in the digitization process,
described below, are
adjusted so that the analog level output in the reference signal are
translated to the corresponding
SMPTE digital value. By creating this mapping in a deterministic way, the
camera is thus forced
into providing a SMPTE compliant digital video information. It is therefore no
longer necessary
to record a long clip of color bars as is common with video tape. It may,
nonetheless, be
preferable to store a single frame of color bars digitally in connection with
each recorded clip of
compressed video.
These components shown in Fig. 3 as well as overall camera and recorder
control
operate under the control of a central processing unit (CPU) 36, such as the
MC68341, available
from Motorola. Inc., which runs under control of a real-time operating system
such as the
2o VXWorks operating system available from Wind River Systems of Alameda,
California.
Management of media files and the disk controller may be performed by any
number of
known techniques, including that disclosed in U.S. Patent No. 5,267,351,
assigned to Avid
Technology and as disclosed in published PCT application WO 93/21636. Data
files are in a
DOS-compliant file format, such as the Real Time File System (RTFS) from etc
bin systems of
Groton, Massachusetts. The RTFS file system is DOS compatible/re-entrant. This
file system
can be supplemented by a media file format known as the Open Media Framework
(OMF),
defined in the OMF Interchange Specifications available from Avid Technology
and available in
the OMF Interchange Toolkit, also available from Avid Technology.
Fig. 4 shows the circuitry of Fig. 3 in more detail. In particular, the
circuit includes a
genlock decoder 60 which receives a composite video signal either from an
external video source
on a first input 62 or from a camera video source through input 64 and outputs
a digital
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composite video signal at 66. The external and camera composite video signals
are also input to
an analog-to-digital converter 68 to generate at an output 70 a digital
composite video signal.
Additionally, a component video signal. such as one comprised of luminance and
chrominance
components, is also received from a camera as an input as indicated at 72. The
components are
s applied to analog to-digital converters for each of the respective
components as indicated in 74. '
76 and 78. The output of these decoders, respectively, 74a, 76a and 78a
provide a digital YUV
digital component video information. A decoder 80 receives digital output from
the composite
video analog-to-digital converter 68 and generates a stream of digital video
information, also in
component form. typically YUV. The outputs of decoders 80 and component analog-
to-digital
l0 converters 74-78 (via YUV bus logic 82) are both applied to what is herein
called a pixel bus 84.
The pixel bus 84 is used to transfer the YUV digital component information in
this system. The
composite video 66 and the YUV component information on pixel bus 84 are both
applied to
encoders 86 and 88 which provide output video signals. In particular, encoder
86 provides what
is called a program out composite video signal, which is a broadcast quality
CCIR 601 composite
1 s video signal. Encoder 88 provides an output composite video signal to a
monitor as indicated at
89 and a luminance only output signal which is applied to a viewfinder, as
described below. The
composite video signal 66 and YUV digital video information on pixel bus 84
are illustrated as
being applied to switches 86a and 88a which selectively apply one of the two
inputs to their
respective encoders 86 or 88. The switch is actually built into an integrated
circuit which
2o embodies the encoder, and hence the switches 86a and 88a are in Figure 4
for illustration
purposes only. They are not intended to signify multiplexers.
Also connected to the YUV pixel bus is a JPEG Codec 92. Although the described
embodiment uses JPEG compression, it should be understood that other types of
video
compression may be used. However, it has been found that, with a commercially-
available
25 Codec, full-motion broadcast quality images can be provided.. Additionally,
because each field is
compressed using JPEG independently of other fields in video stream, editing
of video is not
hindered by the compression algorithm. The JPEG Codec 92 receives input from
and outputs to "
the pixel bus 84. The JPEG Codec is connected to a media data path controller
94. The media
data path controller 94 also receives audio information from the audio
subsystem as indicated at
30 96. The audio subsystem is described in more detail below.
The media data path controller 94 controls compressed data flow between JPEG
Codec
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92 and the media data buffer 98. Additionally. it controls compressed data
flow between the
media data buffer 98 and media storage 100, which is typically a computer
readable and writable
random access recording medium, such as a magnetic disk or an optical disk.
The entire system
is controlled by a central processing unit 102. The control of the media data
buffer 98 and CPU
102 is described, for example, in U.S. Patent 5,045,940 and others as
described above. The
central processing unit has a bus 104 which connects it to a system peripheral
controller 106
which provides control signals to the entire system. For example, it provides
controls to the
media data path 94, JPEG Codec 92, disk controllers for disk subsystem 100,
the YUV bus logic
82, decoder 80, the genlock decoder 60 and the encoders 86 and 88. It is also
connected to a read
only memory 104 which is used to store control programs in the operating
system for the GPU.
A flash ROM 106 is also provided in addition to some volatile memory such as
dynamic random
access memory as shown in 108. Finally, a serial I/O controller 110 may be
used to provide
either an ETHERNET or RS-422 connection to other computers or other equipment.
A more detailed block diagram of the circuitry shown in Figs. 3 and 4 will now
be
described in connection with Fig. 5. As described above. the digitizing
circuitry is controlled by
a central processing unit 100, such as the Motorola MC68341 processor, running
a real-time
operating control system. The central processing unit 100 has a main address
and data bus 102
to which other parts of the system are connected.
Digitizing circuitry includes a GENLOCK circuit 104, which processes composite
2o video signals, and a set of analog-to-digital converters 106, associated
with a synchronization
signal stripping circuit 108, which processes component video signals into a
YUV 4:2:2 format
digital signal. The composite video signal output by the GENLOCK circuit 104
is provided to a
decoder 110, which converts it into a digital component information, similar
to that output by the
analog-to-digital converters 106. The horizontal synchronization signal
(HSYNC), vertical
synchronization signal (VSYNC), and the pixel clock (PIX) are used to
synchronize the rest of
the circuit. The composite signal is provided along a bus 109 to a decoder 110
which translates it
~ into a YUV 4:2:2 digital component signal. The composite signal is also
directed to encoder
152.
The component digital signals are applied to a pixel bus 112 which directs
them
3o through a switch 114, such as a multiplexer, to a raster block converter
116 and memory 118,
which generates picture blocks from the serial pixel data for use and
processing according to the
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JPEG compression standard described above. The memory 118 typically has a size
of 32Kx16.
The transfer of pixel data to the raster block converter 116 bypasses the
central processing unit
(CPU) 100, i.e., pixel data is not written to the CPU's main memory 105. A
JPEG processor 120
interacts with the raster block converter 116 and memory 118 to take a digital
still image
s obtained from the pixel data and compresses it using the JPEG compression
standard to provide
an output as indicated at 122. The JPEG compression may be adaptive to provide
improved
image quality while maintaining good compression levels in accordance with the
teachings of
U.S. patent ~.3~5,450.
As to audio signals inputted, a microphone or line-in signal indicated at 130
is applied
i o to one or more audio coders and decoders (CODEC) 132 which provide a
serial digital output
I 34. The coders are not necessary if the input signal is digital, such as
from a digital
microphone. digital audio tape. compact disc or other digital source, or if
the output signal is
digital. The sampling rate may be any desired rate, but typical rates for
audio include 44.1 KHz,
22KHz and 48KHz. 8, 16 or 32-bit formats may be used, among others. It should
be understood
1 > that the invention is not limited to any particular digital audio format.
Additionally, they may
receive digital input via the bus 136 to convert them to analog output signals
at 138. The serial
audio data 134 and the compressed video data 122 are applied to a pipeline
control circuit 124.
The pipeline control circuit 124 is controlled using synchronization control
information from a
synchronization controller 126 to direct the data into a data buffer 128
typically implemented as
2o a dynamic RAM. A suitable size for this buffer is 2Mx32 and it is typically
implemented
logically as a ring buffer. The pipeline control circuit is implemented in
accordance with the
teachings of U.S. Patent 5.045.940 and PCT publication WO 93/12481. The CPU
100 controls
synchronization controller 126, pipeline control circuit 124 and disk
controllers 140 to direct the
flow of the video and audio data between memory 128 and the disk storage 142.
Two disk
?~ controllers are used for performing conventional striping. However, one
controller may be used
to send commands to circuitry on the drive package which may divide an
incoming stream or
combine an outgoing stream of data in response to commands from a single disk
controller 100.
Striping may be performed at the word level, or at block or byte levels. The
disk controllers and
associated bus to the disk may be any standard controller, such as IDE or SCSI
controllers. It
30 should be understood that the invention is not limited to the type of disk
controller.
The pipeline controller provides a form of local synchronization using demand-
based
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flow control of the media data between the encoders and decoders and the
computer-readable
storage. The movement of data on the pixel bus is through the compressed data
buffer and to the
storage is intermittent, but has an average flow that is comparable to the
continuous,
synchronized flow of a video signal. This flow control accommodates for
statistical variations in
flow due to disk accesses, memory management and other impact on the flow due
to the other
operating system activities. The flow control ensures that an encoder receives
data when the data
is needed and that data is read from a decoder without being dropped. An
additional benefit of
using flow-controlled media data is that no pre-roll time is needed to lock to
an incoming source
or to lock to an output frequency and phase.
This system may also be provided with the capability of providing an output
video
signal generated from the digitized video signal. For example. the pixel bus
112 may be
connected to an overlay circuit 150. The output of the overlay circuit 150 and
the composite
signal 109 may be provided to an encoder 152. The output of the encoder may be
provided back
to the camera which has an input for the view finder 154. Additionally, this
signal may be
~ 5 provided to monitor output 156. In one embodiment of the invention, the
camera's view finder
154 receives a signal not only from the camera, but also from an alternate
source. Using this
capability, the moving picture recorder may have a controller 158 and an
associated memory 160
which may provide additional status information via the view finder in
connection with the video
being recorded. Such status information may be an indication of battery level,
time codes, time
2o of day, function performed (e.g., recording or playback), etc.
The central processing unit 100 also has associated with it a programmable
read-only
memory. such as a flash memory 101 in which program information is stored and
a dynamic
RAM controller 103 and dynamic RAM 105, which are common in the art, for
storing volatile
data while processing. Typically the memory 101 contains an operating system
and other
25 programming code which is kept in non-volatile storage. A suitable size for
this memory 1 O 1 is
4M. A suitable DRAM size is 4Mx 16.
The moving picture recorder may include an additional encoder 162 which
provides a
composite-out video signal with VITC/LTC control information. The input to the
encoder may
be any one of the pixel bus 112, the output of decoder 110, bypassing pixel
bus 112, the output
30 of A/D converters 106, bypassing pixel bus 112 or the output 109 of genlock
circuit 104.
Alternatively, each of these inputs may be applied to its own separate
encoder. The outputs of
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these encoders may be fed to a simple switch allowing for the selection of one
of these outputs.
Additionally, an ETHERNET connection 164 may also be provided.
In one embodiment of the invention, two pixels buses 112 may be used. The
first bus is
the record bus which connects to the outputs of the decoders 110 and 106, and
to the inputs of
the JPEG compression circuitry, via the input side of switch 114, and the
encoders 162 and 152.
The second bus is the playback bus which connects to the output of the JPEG
decompression
circuitry, via the output side of switch 114, and the inputs of encoders 162
and 152.
In one embodiment of this invention, the GENLOCK circuit 104 may be a Raytheon
22071 GENLOCK circuit. The decoder 110 may be a Raytheon SAA7151 decoder. The
t o encoders 152 and 162 may also be either a Raytheon or TRW 22191 full video
encoder. The
ETHERNET circuit, audio modules and disk controller are available in a variety
of forms and are
available from a number of suppliers.
Fig. 6 describes in more detail the audio subsystem, such as shown at the
audio Codecs
132 in Fig. 5. There are generally four input channels and four output
channels: left and right
1 ~ microphone inputs and left and right line inputs, and left and right
balanced audio program out
and left and right headphone out. Each audio channel is provided with a
selector 170 which
selects between microphone and line level inputs, according to the input 172
(which can be
balanced) that it expects to receive. A programmable gain amplifier 174 is
also provided on each
channel. Each audio channel also has a corresponding audio analog-to-digital
converter 176
2o which receives the audio input signal and converts it to a digital signal.
The outputs of the
analog-to-digital converters 176 are digital audio which are applied to the
media data path
device, such as indicate as the pipeline controller 124 or media data path
device R4 in Fig. 4.
These digital signals are then fed to digital-to-analog converters with gain
control as indicated at
178. Digital-to-analog converters 178 receive eight inputs: the digital
signals from the digital
?5 audio from the media path device (four recorded feeds) and the digital
outputs of the
analog-to-digital converters 176 (four live feeds). Digital-to-analog
converters 178 provide eight
outputs to an 8-in by 4-out matrix 180 which selects from the 8-input and
provides the 4 audio
outputs. These four audio outputs are fed to, in pairs, a two-channel
programmable gain
amplifier 182, 184. These are then fed to a microphone or line select device
186 to in turn
3o provide either balanced audio program-out or headphone-out. In one
embodiment, the
analog-to-digital and digital-to-analog converters are implemented with a
Crystal Semiconductor
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422 coder/decoder. The 8-4 switching matrix is an analog switch such as a MAX
33~ available
from MAXIM.
It is also possible to provide a warning tone generating circuit that can be
selectively
applied to either the program-out or headphone circuitry. Additionally, a
speaker on the camera
s may be connected to play the program-out audio.
Control of the amplifiers and switches is provided by computer programming in
a
control program on the CPU. This communication is done over what is indicated
as a QSPI bus
in Fig. ~. In particular, for the variety of possible modes of the system, the
computer has
corresponding output signals which are set when a given mode is selected by
the camera user.
1 o Synchronization of the playback of video and audio through the program-out
channels
will now be described in Fig. 7. The synchronization is performed by creating
a video clock
from a video decoder. such as a 13.SMI-Iz clock as indicated at l 90. An audio
clock synthesizer,
such as a Crystal Semiconductor CS 1522 audio clock synthesizer, as indicated
at 192, receives
the video clock from the video decoder and generates a master audio clock,
such as a I2.288MHz
15 clock. This master audio clock is then provided to an audio clocking system
194 in the media
data path device which generates a plurality of clocks to the audio subsystem.
The display 30 shown in Fig. 1 provides further advantages over the prior art.
In prior
art recorders. the linear recorder performs the function of recording and
perhaps playback of the
material recorded on the single videocassette in the system. Editing of the
material must be
2o delayed until the videocassette is mounted in an analog video editor, or,
more recently. a
non-linear video editor after the video material has been digitized. One
aspect of the present
invention provides a digitized, compressed-form material which may be readily
edited. In one
embodiment of the invention, the recorder includes an editing system, such as
the editing system
described in U.S. Patent 5,267,351 and PCT published application W093/21636.
the disclosure
25 of which is incorporated by reference herein. The editing system is also
described in U.S. Patent
Application Serial No. 09/898,878 (Publication No: US/2003/0034997 A1). The
inclusion of the editing system allows a user to edit the video material
recorded at the recording
site, even prior to, or in lieu of. editing in a studio. This is particularly
advantageous if the
material must be broadcast immediately. Therefore, the video and audio signals
may be
3o recorded. edited and broadcast from the field in a very short period of
time. During editing,
information is played back through the digital video pipeline through either
the view finder or
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other display. Dllrlllg editing it is possible to display video through an
external video port, or to
have the external video port transmit live video. The arrangement of a variety
of video inputs
and outputs provides switching capabilities in the camera similar to those
found in a television .
broadcast studio.
The recorder 62 also may include a number of pressure-sensitive or other
suitable
controls 64 to provide recording and edit functions for the material displayed
on display 30. The
display 30 may be of a LCD or other suitable thin panel type.
Having now described a few embodiments of the invention, it should be apparent
to
those skilled in the art that the foregoing is merely illustrative and not
limiting, having been
presented by way of example only. Numerous modifications and other embodiments
are within
the scope of one of ordinary skill in the art.
For example, analog-to-digital conversion circuitry may be eliminated from the
camera
because processing of analog signals is no longer necessary.
Additionally, although a media package is described herein as removable, it
need not be
removable. Additionally, disk drives may be external to the camera, for
example, in a rack
mount. Rather than record to disk, an output may be directed to a computer
network, such as an
ATM network, or a transmitter, such as a cellular, satellite, or microwave or
phone link. By
providing removable disk drives. a disk drive becomes filled with recorded
video material, a
new, empty disk drive can be inserted to replace the filled drive, similar to
replacement of a
2o video tape. It is also possible to have two hard disk drive packs, and thus
two receptacles in the
video recorder 24 of the type shown in Figs. 3 and 4. With such a system,
continuous recording
from one disk drive to the next can enable an indefinite amount of time to be
recorded without
loss of information due to switching of recording media.
These and other modifications are contemplated as falling within the scope of
the
? 5 invention as defined by the appended claims.
i
