Note: Descriptions are shown in the official language in which they were submitted.
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WO 95/14994 2 1 7 ~1 ~ 6 PCT/US9.~/13600
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ENDLESS TAPE VIDEOCASSETTE STRUCTURE
Fleld of the Invention
This invention relates to endless tape videocassettes and
more particularly to improved endless tape videocassettes
which have longer play time, lower cost and/or higher
reliability than existing endless tape videocassettes. The
invention also relates to systems for recording on and
utilizing the output from such videocassettes for repeated
display of short audio/video clips, and for random access to
either selected analog or digital data units for display or
for other seiected functions. Indexed data units received by
the system may be stored on the endless tape for later
viewing or may be randomly selected for real-time viewing.
Backqround of the Invention
There are many applications where a low-cost storage
medium is required for analog or digital data and, in
particular, for analog or digital video data. In addition to
being far lower cost tharl existing storage mediums, such
mediums should also provide relatively large capacity,
comparable to that of a hard disk drive, and should permit
data thereon to be randomly accessed at reasonable speeds.
The retrieved data could then be used to provide randomly
accessible video images for display on a standard television
or on a computer display, to provide low cost bulk storage
for a computer or for other purposes. The ability to
randomly access large numbers of video frames stored on a
storage medium for viewing by, for example, use of multilevel
menu techniques or other search technigues known in the art;
could permit large and relatively expensive printed
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documents, such as service manuals or various catalogs, to be
;n~ nl:ively sent to users, either as burst transmissions
within a television or cable signal, by mail or by other
suitable means, to be stored in compact form, and to be
easily viewed, when desired, through a standard videocassette
recorder (VCR) and a standard television set or a computer
monitor. In addition to the ecological advantages of reduced
paper consumption and waste which would result from this
practice, it would also permit faster access to desired
information .
One way to achieve these objectives is to use an endless
tape videocassette as the storage medium. Another situation
where an endless tape videocassette might be useful is where
relatively short audio/video clips, for example a clip
lasting l to 5 minutes, is to be repetitively displayed for
advertising, informational or other purposes. For example,
demonstration or promotional clip may be repetitively shown
to people passing a trade show booth, an in-store or mall
display, a store window, or in other similar applications.
Heretofore, the clip would normally be reproduced as many
times as possible on a standard linear cassette and then
either manually or automatically rewound when the end of the
tape was reached. ~ormally, the VCR stops when the end of
the tape is reached, and human intervention is re~uired to
rewind and/or replay the tape for subse~Euent replay of the
clip. An improved, endless tape videocassette which would
permit the showing of such clips without rewinding and
restarting the tape.
Some efforts have been made in the past to provide
relatively long endless tape videocassettes which cassettes
are of a size to fit in a standard VCR. Examples of such
WO95/14994 21 771~6 PCT/US94/l3600
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prior efforts are shown in U.S. Patent ~o. 4,462,553, which
mechanism is adapted for holding only a relatively short tape
and in U.S. Patent ~os. 3,925,820 and 4,454,976, both of
which involve having a storage compartment in which a portion
of the tape is gathered in a tortuous or random serpentine
conf iguration with substantial contact between various
portions of the tape gathered in the storage compartment.
The tape in the ' 553 patent is also caused to run over f ixed
surfaces. The tape passing over a fixed surface or coming
into substantial contact with itself causes electrostatic
charges or attraction which can cause the entire mechanism to
jam. The ' 820 and ' 976 patents require a special mechanism
to deal with electrostatic charge, but it is difficult to
remove such charges and the cassettes of these patents are
therefore also subject to jamming and have not enjoyed
commercial success . The mechanisms of the ' 820 and ' 976
patents are also relatively complex ana relatively expensive
to fabricate. Another problem with at least some of the
prior art endless tape cassettes is that they do not apply a
controllable tension to the tape and therefore cannot adjust
tape tension to accommodate variations in tape paths found in
various VCRs. They therefore require a specific tape length
for each particular VCR design, something which is not
practical in consumer applications and in most commercial
appl ications .
A need, therefore, exists for an improvea endless tape
videocassette which provides minimal complexity, may be mass
produced at relatively low cost, permits relatively long
lengths of tape to be stored in the cassette while assuring
minimal passage of the tape over fixed surfaces in its travel
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path, assures minimal intertape contact during tape travel,
and provides controlled tape tension when the cassette is in
its operative or play state.
Summary of the Invention
In accordance with the above, this invention provides an
endless tape videocassette and systems for the use thereof.
In particular, the cassette includes a reel having a f irst
plurality of rollers mounted at predetermined positions
thereon and a second plurality of rollers mounted at
predetermined positions spaced from the first plurality of
rollers. For preferred en~bodiments, the first plurality of
rollers are mounted on a supply reel of a tape cassette and a
second plurality of rollers are mounted on a take-up reel of
such cassette. An endless videotape is threaded in the
cassette so as to pass over each of the rollers with the tape
passing between the first and second plurality of rollers at
two places along the tapes length. The cassette has an
operative state when it is in a videocassette recorder (VCR)
with a portion of the tape between the f irst and second
plurality of rollers being pulled from the cassette into
contact with a read/write head of the VCR and an inoperative
state with the tape wholly within the cassette. At least one
of t~e reels is rotated to take up the tape pulled from the
cassette when the cassette is to be returned to its
inoperative state. The tape is threaded in the cassette so
as to maintain tension on substantially all portions of the
tape when the cassette is in at least the operative state,
whereby there is substantially no slack section of the tape
for the operative state, and is also threaded so as to insure
substantially no contact between portions of the ta~e for th~
Wo 95/14994 21 7 715 ~ PCT/USg4/13600
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operative state. For preferred embodiments, the tape is
threaded so as to maintain some tension on substantially all
portions of the tape when the cassette is in both its
operative and inoperative states.
For some embodiments a tensioner is included for applying
tension to at least one of the reels. The tensioner may
include a sprin~ arm for at least one of the reels which
biases the reel in a rotational direction so as to maintain
tension on the tape. The bias applied to the reel by the
spring may also be operative to rotate the reel to take-up
tape pulled from the reel when the cassette is to be returned
to its inoperative state. The tensioner may include a spring
arm for applying rotational bias to each of the reels and at
least one of such spring arms may also be operative to
perform the tape ta~ce-up function. Only one of the reels may
be rotatable, and where this is the case, and there is a
tensioner, the tensioner would apply tension to this reel.
For some pmho~; ts, the second plurality of rollers has
first and second groups of rollers which groups are spaced
f rom each other, with the tape being wound between
corresponding rollers of each group to form a plurality of
adjacent, noncontacting tape loops. The endless tape is
preferably a seamless tape.
A plurality of indexed image frames, fields or other
addressable data units are storable on the tape of the
cassette for preferred embodiments, with the cassette being
usable with a system which includes a cassette computable VCR
and a circuit utilizing outputs from the VCR for a selected
function. For example, image frames stored on the tape can
be successive video frames of an audio/video clip, with the
VCR running the tape continuously. A display device would
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also be provided with the outputs from the VCR being applied
to cause the clip to be repetitively displayed on the display
device. Alternatively, a means could be provided for
randomly accessing data units from the tape which are
outputted from the VCR, the VCR running continuously when in
this mode without any requirement to operate forward or
rewind controls. Where the randomly accessed data units
contain digital data, a computer could be provided, with an
indication being outputted from the computer of digital data
required, and a means being provided which is responsive to
the indication of digital data for randomly accessing the one
or more data units containing the required digital data and
applying such data units to the computer. The randomly
accessed data units can also be indexed video image frames
with a display device being provided along with some means
for indicating a video image to be displayed. A device could
then be provided which is responsive to index markings on the
video images and to the indication of a video image to be
displayed for randomly selecting the video image to be
displayed from the image frames outputted from the VCR. A
frame memory is also provided for storing the image frame
being displayed, with the selected video image being stored
in the frame memory. The image frame stored in the frame
memory mav then be repetitively read out to control the
display on the display device. Burst transmissions of image
f rames may also be received at the system f rom a remote
source, with the received image frames being applied to the
VCR for recording on the tape of the cassette or being passed
directly to a decoding device for real-time viewing.
While the random accessing of data units from an endless
tape videocassette is preferably performed from an endless
tape videocassette of this invention, and for reasons
wo95/14994 21 771~6 Pcrlu594113600
-7-
previously discussed the endless tape videocassettes of this
invention are the only such cassettes which are in~rr-~n~ive
to fabricate and which can store and reliably provide a
reasonable volume of information, these random access
techniques could be practiced using other endless tape
cassettes .
The foregoing and other objects, features and advantages
of the invention will be apparent from the following more
particular description of preferred errbodiments of the
invention as illustrated in the accompanying drawings.
Brief Description of the Drawinqs
FIG. l is a top sectional view of a videocassette of a
first embodiment of the invention shown in its operative
state in a VCR;
FIG. 2 is a top sectional view of the cassette of FIG. l
shown in its inoperative state;
FIG. 3 is a top sectional view of an endless tape
videocassette of a second embodiment of the invention shown
in its operative state in a VCR;
FIG. 4 is a top sectional view of the endless tape
videocassette of FIG. 3 shown in its inoperative state;
FIG. 5 is a bloc~ schematic diagram of a system in which
the endless tape videocassettes of this invention might be
utilized .
Detailed Description
Referring first to FIGS. l and 2, an endless tape
videocassette lO for a first embodiment of the invention is
shown in its operative state when mounted in a VCR (only
parts of the VCR being shown) and in its inoperative state,
wo 95ll4994 PCTIUS94113600
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respectively . The cassette has a f irst or supply reel 12 and
a second or take-up reel 14 mounted in a housing 16. Reel 12
has rollers A, B and C mounted thereon in a pattern which is
triangular for the embodiment shown while reel 14 has rollers
A', B' and C' mounted thereon. Reels 12 and 14, mounted on
their own bearing surfaces, fit over corresponding spindles
18 and 20 of the VCR and rotat~e free of these spindles. A
biasing spring 22 is connected at one end to a pin or hub 24
which is fixed to housing 16 and is attached at its other end
to reel 12 through a cam 26. Similarly, a biasing spring 28
is attached at one end to pin 24 and at its other end to reel
14 through a cam 30. Suitable elastomeric tensioners may be
used in lieu of the springs.
The cassette housing 16 has rollers 32, 33, 34, 35 and 38
mounted thereto. Pins may in some cases ~e substituted for
rollers 33 and 34, but rollers are preferable. An endless
tape 40 is mounted on the cassette 10 with the cassette in
its inoperative state (FIG. 2) so as to pass under roller 32,
over roller 33, across the front of the cassette, over roller
34, under roller 35, past roller A' and hub 37 of reel 14,
over roller B' and under roller C', past roller 38, around
roller C, around roller B, over roller A, and back to roller
32. The path for tape 40 when the cassette is in its
operative state shown in FIG. 1 will be described shortly.
Tape 40 is preferably a seamless tape loop which is either
manuf actured as one piece or has the ends of the tape
seamlessly joined together using techniques for forming such
seamless joints which are known in the art. Spring 22
applies a biasing force to reel 12 which is in the
counterclockwise direction and spring 28 applies a biasing
wo 95/14994 21 7 7 ~ S 6 PCT/US94/13600
_g_
force to reel 14 which is in the clockwise direction. ~he
result of these biasing forces is to maintain tension in the
tape 40 throughout substantially its entire travel path.
FIG. 2 also shows a pair of guide rollers D and E which
are part of the VCR, these guide rollers being shown in the
position they would normally be in when cassette 10 is first
inserted into the VCR. Guide rollers D and E are mounted on
tracks in the VCR and engage the tape along the long section
thereof between rollers 33 and 34 to pull a portion of the
tape from the cassette and into engagement with read/write
head 51 of the VCR (FIG . 1 ) . When the cassette is in its
operative position shown in FIG. 1, it is seen that the path
of the tape 40 changes so that, starting again at roller 32,
the path of the tape is under roller 32, over roller 33, over
pivot arm 54 of the VCR, through rollers 55 and 56, through
pinch rollers 58 and 60 (roller 58 being the erase head)
around roller D, around read/write head 51, over rollers E
and 62, through drive capstan 66 and pivot arm 70, over
rollers 34 and 35, over rollers A', B' and C' of reel 14,
over roller 38 and rollers C, B and A of reel 12 to its
starting point at roller 32. In each instance where the tape
passes between two rollers, one of the rollers, generaIly the
smaller one, is raised or lowered to the position shown after
the tape has been drawn out to the positions shown.
From FIG. 1 it is seen that when the cassette is in its
operative position, no part of tape 40 makes contact with
itself, and there is, at most, point contact with static ( as
opposed to rolling) surfaces so that static charge does not
build up on tape 40 as it moves through its travel path.
Further, as the tape is pulled from cartridge 10 into the
VCR, reels 12 and 14 are rotated against the biasing forces
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of springs 22 and 28, respectively, so that both reels are:
under biasing pressure when the cassette is in the VCR, thus
assuring proper tensioning on the tape regardless of the VCR
in which the cassette is being used Therefore, the cassette
may be utilized in a variety of different VCF~s having
different tape length requirements. This is in contrast to
some prior art cassettes which do not have such tape
tensioning capability. When the cassette is to be released
from the VCR, rollers D and ~ return to the positions shown
in FIG. ~. This results in a slack in the secticn of tape
between pins 33 and 34 which slack is taken up by the
-ota~ion of reels 12 and 14 in response to the biasing forces
applied thereto by springs 22 and 28, respectively, to the
positions shown in FIG. 2. From FIGS. 1 and 2, it is seen
that reel 12 is rotated approximately the same as reel 14 so
that there is essentially the same amount of tape on both
reels. The amount of differential will be determined by the
length of the tape loop and by the tension applied to each
reel by the corresponding spring. The cassette is thus
returned to its inoperative state in preparation for ejection
f rom the VCR .
FIGS. 3 and 4 illustrate an endless tape videocassette
10 ' for an alternative embodiment of the invention. For ease
of understanding, common elements of cassettes 10 and 10'
have been given the same reference numerals/letters. In
comparing the figures, it is seen that the main differences
between the embodiment are that reel 14' has eight rollers
F-M arranged in two spaced groups of four rollers each,
rather than only three rollers, and that reel 14' is
stationary rather than being rotatable as for the first
embodiment. Since reel 14' is stationary, a biasing spring
WO95114994 1771S~ PCT/US94/13600
is not attached to this reel to provide tension on the tape
or to facilitate taking up of tape when the cassette is being
returned to its inoperative state. Therefore, for this
embodiment of the invention, the take-up function is
performed solely by rotation of supply reel 12 in a
counterclockwise direction. Since unlike the first
embodiment where some of the take-up function is accomplished
by a small clockwise rotation of take-up reel 14, all of the
take-up is performed by reel 12 for the second embodiment, a
somewhat greater rotation of this reel is required. The
rotation of reel 12 in the counterclockwise direction for
tape take-up may be accomplished under the action of
tensioning spring 22 for the second embodiment in the same
way as for the f irst embodiment . However, since a standard
VCR imposes a short counterclockwise rotation on the supply
reel when the cassette is to be removed for the purpose of
taking up the tape pulled into the VCR, this rotation can
also be used to perform the take-up function for the tape and
is considered to be the preferred way to perform this
function. Therefore, if hub 42 is sprocketed to fit on the
supply reel spindle 18, supply reel 12 will be driven by the
proper amount to perform the tape take-up function when the
eject button on the VCR is pressed. Tape take-up for the
first embodiment could also be performed in this way, and it
is normally preferable that it be performed in this way.
The primary advantage of the embodiment shown in FIGS. 3
and 4 is that it permits more tape to be stored in the
cassette than for the previous embodiment. While eight
rollers are shown on take-up reel 14' for the cassette 10',
the actual number of rollers on take-up reel 14' can vary
with the length of tape desired. If a signif icantly greater
wo 95114994 ~ 5 PCTIUS9411360
number of rollers are provided~ on reel 14', the rollers will
have to be made smaller so as to avoid contact between
adjacent portions of the tape. Another potential problem is
that the tape passing over a large number of rollers,
particularly when there are sharp bends in the tape as it
passes over the rollers, exerts tension on the tape which
resists the tape drive force of the VCR. This tension can be
sufficient for the embodimen~ shown in FIGS. 3 and 4 so that
tensioner spring 22 is generally not reouired. However, if
the number of rollers provided on reel 14 ' becomes excessive,
this tension may get so great as to inhibit the ability of
the VCR drive mechanism to move the tape. This tension or
friction problem will in all li~celihood limit the numoer of
rollers which can be placed on reel 14' rather than available
space on the reel for such rollers.
Another problem for the embodiment of FIGS. 3 and 4 is to
ensure that rollers F-M have a proper vertical alignment with
the tape 40 entering cassette lO ' . In the f igures, this is
accomplished by mounting the rollers to reel 14' with the
reel being free to move vertically but not rotate. When the
cassette is inserted into the VCR, the cassette is brought
down over the drive mechanism with the reel sitting on top of
a small housing that assures there is no engagement with the
take-up drive spindle 50. The spindle and reel are designed
to interact so as to raise reel 14' to the proper height for
alignment of the rollers. Alternatively, since reel 14' does
not rotate, the reel can be dispensed with and rollers F-M
can each be mounted on a corresponding pin which is fixed to
housing 16. The rollers can be spaced from the housing on
the pin to achieve substantial alignment and can be mounted
for small vertical movement on the corresponding pin to
permit self-alignment of the rollers ~ith tape passing
thereover .
. . _
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The cassette lO shown in FIGS. l and 2 can typically
store approximately thirty-six inches of tape which will
provide approximately twenty-seven seconds of viewing time on
- a standard VCR in standard play (SP) mode. The second
embodiment shown in FIGS. 3 and 4 can be adapted to store
substantially longer lengths of tape, with the embodiment
shown being adapted for storing approximately 130 inches of
tape . lf a tape speed of I . 3 inches per second is assumed,
this results in approximately 96 seconds of viewing time.
This amount of tape can also be used to store approximately
lOo megabytes of data. Since videocassettes are relatively
inexpensive to produce, it should be possible to produce such
a cassette for a price in the ~l.oo range which is roughly
l/50 to l/lOo the cost for similar storage capacity on
existing rotating memories such as magnetic hard disk drives.
Endless tape videocassettes are thus shown which achieve
the following functions: ~
(l) provide a path for the tape of sufficient length to
provide the requisite playing time;
(2) assure that when in the operative or play state, the
path for the tape does not pasfi over any significant static
surf ace and that there is no inter-tape contact so as to
avoid static charge being formed on the tape.
(3) provides for setting the proper tension, as
established by the published specifications for the type of
VCR for which the cassette is intended (typically VEIS), for
the tape when in the operative or play state;
(4) provide for the recovery and storage of the tape
that is pulled out of the cassette by the VCR at the time the
cassette is to be ejected.
WO95/14994 2~ ~56 PCT/US94/13600
-14-
In the discussion above it has been assumed that cassette
10, 10' is to be used in a VHS VCR. However, with
modifications to the cassette which would be obvious to one
skilled in the art, the techniques of this invention could
also be applied to operate in other "M-load" variety machines
such as VHS-C and 8MM, or with "U-load" m~ hinf~s such as Beta
cassettes .
FIG. 5 shows a system in which the cassettes of this
invention might be utilized ~or in which other endles-s tape
cassettes might also be utilized). Referring to FIG. 5, a
standard VCR 60 is shown, which VCR is of the proper type to
play the cassette loJ10' being utilized. Output line 61 from
the VCR, which line contains the digital or analog data read
from the tape is applied to a decoder/processor 62. As will
be described in greater detail later, the output from the
decoderJprocessor may be applied to cause a display on a
standard TV set 64, may cause audio signals stored on the
tape to be applied to an audiocassette recorder 65 or may
apply such signals to a speaker 66 which speaker may be par.
of TV set 64 or may be separate. A personal computer 67 may
also receive outputs from decoderJprocessor 62 or such
outputs may be applied to a videocassette recorder 68.
Computer 67 may include a bulk storage 69 on which material
read from the VCR is stored. The computer may also have a
display monitor 70 on which video images are displayed in
lieu of being displayed on TV set 64 and a keyboard 72 which
may be utilized for inputting data requests into the
computer. Speaker 66 may be associated with computer 67 or
separate speakers may be provided f or the computer .
VCR 60 may also receive inputs from remote control
interface 88 over line 76 to control the functions in the
VCR. Such functions may include: starting the recording of
Wo g~/14994 l 7 71 5 ~ PCr/uss4ll36oo
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information, stopping the recording of information, starting
the playing of information, or stopping the playing of
information. Control may also include changing channels on a
tuner or gating an external signal source 74 so that the
signal source is routed to the tape or to decoder 62 for
real-time browsing. In particular, rather than recording a
selected incoming video frame on the tape of cassette l0, the
frame can be routed directly to decoder 62 for storage in
VR~M 84, and for display.
The code to control the VCR may come from a variety of
sources. The operator may program the VCR using the
interface provided by the manufacturer. Published codes,
such as VCR Plust, may be used to ease the burden of
programming the VCR. However, since burst transmissions are
very short and preferably not repeated a large number of
times, it may be difficult to set the timer on the VC~ with
sufficient precision to receive and record the desired
information. It is therefore preferable that the transmitted
data be encoded with information to be used by decoder 62 for
the purpose of starting and stopping the VCR in record mode.
The codes and transmission times would account for the start
delays associated with the VCR mechanisms and the varying
lengths of the tape loops . Other options f or obtaining the
requisite time and code information would be apparent to
those skilled in the art.
The code for the desired data could be provided to a user
in a number of ways, For example, a particular channel on
the cable network could be dedicated to providing required
codes to users, either by displaying such code sequentially
Wo 95/14994 PCTIUSg4113600
--16--
or by responding in some manner interactively to a user
request. Such codes could also be published in a guide,
newspaper or other periodically published document which
users of the system would receive. This document would
indicate when a particular type of information, for example a
particular catalog, is being transmitted and the code for
such catalog. It is also possible that a company, rather
than sending a user a catalog, could send the user a postcard
advising as to the time and code for the transmission of the
company' s catalog or of an update to the company' s catalog.
Other options for obtaining the requisite time and code
information would be apparent to those skilled in the art.
Decoder processor 62 contains an analog signal
conditioning circuit 81 to which the signal on line 61 is
initially applied. This circuit provides termination,
clamping, filtering and ampliication of the input analog
video signal. Termination circuitry is, for example,
provided to prevent reflections from the end of. a cable
signal. Since the direct current offset of a video signal
may vary, clamping circuitry is provided which assures that
the sync pulses do not exceed zero volts. Filtering
circuitry is incorporated to remove unwanted noise
frequencies and the processed signal is then amplif ied by an
automatic gain control circuit. These are all standard
functions which do not form part of the present invention,
and the functions performed by signal conditioning circuit 81
will vary depending on the nature of the outputs on line 61.
For example, if digital outputs appear on line 61, different
signal conditioning functions will be required.
The output from circuit 81 is applied to a frame address
decoder 82 and also to a video capture-A/D conversion circuit
83. Each frame or other identifiable data unit is stored on
WO9S/14994 ~t 77~S~ PcrluS94113600
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cassette 10 with a suitable index marking . For example, U. S .
Patent ~o. 4,517,598 to Van Valkenburg, et al. teaches one
way in which index markings may be placed on the visible
portion of video frames stored on videotape to permit
subsequent retrieval. Standard biphase coding of the type
now used on video disks may also be used for encoding the
frames. For one embodiment, biphase coding is used on
horizontal lines 17 and 18 of each video fra.me, which lines
are not normally displayed. The analog video signal being
applied to decoder 82 may be applied to a standard video
detector and sync separator (such as an LM 1881 manufactured
by National Semiconductor ) . Such circuit determines where
the frame number exists by using internal timing and the
vertical and horizontal sync pulses f rom the analog video
signal. When the proper location time is determined, a flash
analog to digital converter converts the analog video signal
into digital data which are stored into a RAM. A standard
software algorithm is then used to process the data bytes
into a frame number which frame number may be encoded using a
variety of known schemes. For example, 24-bit biphase
encoding such as that used on laser disks may be utilized.
Standard SMPTE time code may also be utilized. The start of
the frame address is det~rm;n~d by circuitry which counts the
horizontal sync pulses to determine corre~-t line location.
Standard software may be used for controlling the flow of
dat a .
The frame (or other data unit) which is desired for
display or other use is inputted into decoder 82 from a
central processing unit 85 which is preferably a
microprocessor such as an Intel 80186. The frame decoder
compares the inputted frame address against the received
frame numbers until a match is found. Since the tape being
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read is an endless tape, there is never a problem of the tape
being past the desired address or information and the access
time for a particular frame will be no greater than the
length of the tape. For example, for a tape length providins
l00 seconds of storage, the maximum time to randomly access a
given frame would be l00 seconas, and the a~erage time would
be 50 seconds, or less than one minute.
Several techniques may be used to improve the access ti~.e
of materials on the tape. If the volurne of data is small,
the data may be repeated on the tape. Additional memory may
be used to provide multiple frame buffers for storing
additional amounts of information. Predictive algorithms may
be employed to anticipate which data units would be
selected. Other options for improving access time would be
apparent to those skilled in the art.
When a match is detected by decoder 82, it generates a
signal to circuit 83. Circuit 83 is a data acquisition
system which, for analog inputs, continuously converts the
analoq ~rrSC, PAL, or SECAM signal into a digital format.
Existing circuits are utilized to determine where the data
begins by using internal timing and the vertical and
horizontal sync pulses of the analog video signal. When a
signal is received from decoder 82, an analog to digital
converter CJilV~!L ~S the analog signal into d ~ital data bits
which for video signals may be applied to and stored in a
standard video random access memory (VRAM) 84.
VRAM 84 functions as a frame buffer and other memories
capable of performing the frame buffer functions may be
utilized. A VR~M is particularly suited for this function,
being a very f ast access time random access memory which
permits analog video signals to be stored digitally in real
time. A number of memories of this type are commercially
WO95/14994 1771~6 PCT/US94/13600
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available. VR~M 84 also includes circuitry to clock data
directly into the VRAM from the video capture circuit 83.
Where the data being read from the cassette is not video
data, a suitable memory may be substituted for VRAM 84 or the
data may not be stored in aecoder 62 at all, being applied
directly for, for example, computer 67 or bulk store 69. CPIJ
85 also has access to the VR~M and may modify the information
received from the videocasselte as desired. Tt may, for
example, add information to be displayed with a video frame
or may reformat the data for display in a variety of known
ways . The specif ic processing which is done on the data does
not form part of the present invention.
CPU 85 also has its own system RA~S 86 and a ROM 88 for
storing the system program or operating code. These are
standard components and are used in a standard way by the CPU
for performing its various functions and for controlling the
operation of the decoder/processor 62.
A remote control interface 88 decodes a parallel or
serial data stream from a suitable remote control unit into
user cl 1c which are applied to CPU 85. The decoding may
be performed in hardware or via software algorithms and
translation tables. The remote control may for example be an
infrared remote control producing a pulse code modulated
serial stream of infrared data which is trans1 ated into user
keystrokes through a software algorithm running on an 8051
microprocessor. Such remote control interfaces are known in
the art. The remote control itself (not shown) may be a
standard VCR remote control, may be one of a variety of
generic controllers which can be programmed to operate with a
variety of devices or could be some other type of controller
such as a joystick, mouse or other controller such as that
used with Pho~o CDs which prcvide interactive video access
WO95/14994 2 17 ~15 ~ PCTIUS94113600
--20--
and the ability to move a cursor. The exact nature of the
remote control does not form part of the present invention,
and any one of a variety of such controllers, whether
currently existing or subseo~uently developed, may be used for
this function, depending on application. The manner in which
the controller may be utilized~ to select a desired video
display will be discussed Iater.
CPU 85 may also provide inputs to a character generator
digital overlay circuit 89 which allows text and graphics to
be superimposed upon the user ' s screen (whether TV set 64 or
computer monitor 70). Character generator 89 may be a
separate device which controls type fonts, graphic
characters, and other special effects to be displayed, or
these functions may be programmed into CPU 85. Again,
hardware and software for performing these functions are
known in the art and existing devices can be used for
performing this function.
The outputs from both VRAM frame buffer 84 and character
generator 89 are applied as inPuts to a standard video
generator 90 which converts the digital video data into an
NTSC, PAL, SECAM, or other suitable analog video signal.
Standard video generators known in the art may be utilized to
perform the necessary D/A conversions and the timing and
synchronization functions. The- signal may be RF modulated
and then sent to TV set 64 and/or VCR 68. VRAM 84 is
repetitively read out at a rate so as to permit refresh of
the display on TV set 64.
Decoder/processor 62 also includes a power supply 91 for
providing proper positive and negative DC voltages to the
various components of decoder/processor 62, an expansion port
92 and an audio generator 93. The expansion port provides an
interface to a variety of peripheral deYices, and in
WO 95114994 1 7 71~6 PCT/US94/13600
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particular provides a bidirectional path between CPU 85 and
- personal computer 67. Expansion port 92 may also provide
information directly to bul~c store 69 or the provision of
information to this store may be through personal computer
67, ~ome/industrial appliance control ~systems, security
systems, and any of a number of other custom devices may also
be connected to receive video or digital data from VCR 60
through decoder/processor 62, or to provide in~uts to the
decoder/processor to, for exampIe, ranaomly select a video
frame for display. Audio generator 93 converts digital audio
data into analog sound signals. This is a standard device
which performs the DJA conversion and amplification to
produce a signal suitable for output to produce audio for TV
set 64, audiocassette recorder 65 or, through expansion port
92 to personal computer 67 or other devices connected to tl:~e
expans ion port .
Where VCR 60 is being used to repetitively run a short
audio/visual clip, the VCR can be connected to TV set 64 in
standard f ashion . For random viewing of a cata~og, manual or
other collection of video images, a variety of techniques
could be utilized to generate the frame addresses applied by
CPU 85 to decoder 82. One option is to have interactive
video access such as currently used with Photo CDs. For this
mode of operation, a separate card or other document is
provided with the cassette which either includes a reduced
image of each frame or some other identification fcr the
frame, along with a number which the user can input if the
user decides to view such frame. The cassette would also
contain a decoder frame correlating the user input codes with
corresponding frame addresses. The user would then input a
suitable two or three digit number, depending on the number
Wo 95114994 2 1 7 ~ ~ S ~ PCTIUS94/13600 *
--22--
of frames on the cassette, which number would be converted
into a frame address either in CPU 85 or decoder 82,
depending on where the decoder table is stored.
A secor~d option is to use a multi level menu to perform
frame selection. With this mQde of operation, when a
cassette is initially loaded into the VCR, it causes a screen
sign-on display which is a f irst level menu. The user can
make selections from this menu either by inputting an
appropriate number from a controller, or by moving a curser
where a controller having this capability is provided. The
selection from the first level menu may result in a frame
having a second level menu from which a further selection can
be made. This process may be repeated for successive menu
levels until the desired frame to be displayed is reached.
Other techniques for selecting a particular data frame known
in the art may also be utilized.
Where the information stored on a cassette is digital
data rather than video data, such data would be randomly
accessed by utilizing suitable decoder techniques, such as a
decoder table, preferably carried by the cassette itself,
which can be loaded into decoder 62 into CPU 85 or into
personal computer 67 and could be utilized to convert data
access requests from the computer into frame addresses (or
addresses for other addressable data units) being outputted
f or the tape cassette f rom VCR 60 .
A system is thus provided which can very inexpensively
store video images or other data in either analog or digital
form and can permit such data to be either sequentially or
randomly accessed with a response time which is reasonable
for many applications. It also provides a relatively
;nPYpPnqive way to send large amounts of data to users for
,
WO95114994 21 771S6 PCT/US941~3600
-23-
various multimedia applications, including sophisticated
computer games, for service manuals, catalogs, and the like.
Further, in the discussion so far, it has been assumed that
the data, whether video frames or other, are received and
stored in the form in which they are to be displayed and/or
otherwise used. However, various techniques are available
for increasing the amount of information which may be stored
on a given endless tape casset~e. First, video data,
particularly color images, typically re~uire 8 or more bits
per pixel to achieve optimum quantization. However, where
lower quantization levels are acceptable (i.e., less color
depth) then the number of bits per pixel can be reduced,
permitting a signif icant increase in the numoer of
addressable images available. For significantly lower
quantization levels, this may result at least an order of
magnitude increase in the number of addressable images.
Second, various compression techniques known in the art
may be utilized to further reduce the amount of information
required to be displayed for each image frame and to thus
significantly increase the number of image frames which may
be stored on a given length of endless video tape. For
moving pictures, MPEG compression techniques may be
utilized. For other data units, appropriate compression
technigues such as run length encoding, Huffman encodi~og,
and/or Lempel Zev encoding may be utilized to achieve
significant levels of compression. Where the information
stored on video cassette 10 is in compressed form, an
additional decompression unit may be provided between circuit
83 and VR~M 84 to decompress an incoming frame before it is
stored in the VR~M. Alternatively, the information may be
initially stored in VRAM 84 in compressed form and this data
may then be processed in CPU 85 to be converted to its clear
-
WO 9!i/14994 ~ PCTIUS94113600
21771~6
-24 -
or decompressed form. It may thus be possible to store
quantities of data on an endless loop videocassette which are
one to two to orders of magnitude greater than those
previously discussed.
While two specific embodiments for the endless tape
videocassette have been shown and described in detail, and
various modif ications on such cassettes have been discussed,
it is apparent that other modif ications could be made in such
cassettes, for example in the number and/or placement of
rollers on the reels. The tensioning mechanism, if required,
could also be different than the tensioning springs 22 and 2
shown, with other spring mechanisms such as coil springs
being utilized, or with some type of elastimer being used.
The rollers could be replaced with some type of bearing or
other suitable mechanisms might be utilized to prevent any
substantial static contact for the tape when the tape is
being run in the VCR. Similarly, the system shown in Fig.
is for purposes of illustration only and other suitable
mechanisms could be utilized depending on the application.
Thus, while the invention has been particularly shown and
described above with reference to preferred embodiments, the
foregoing and other changes in form and detail may be made
therein by one skilled in the art without departing from the
spirit and scope of the invention.
What is claimed is:
