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Claims  |
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What is claimed is:
1. An encoding method for producing specific encoded data comprising the
steps of:
calculating the data occupancy of a decoding buffer memory of a particular
size that is used when decoding the encoded data during reproduction,
defining the allocated code size of a particular period based on the
calculation result, and
compression coding the signal of a particular period to the allocated code
size,
wherein the data occupancy is calculated on the assumption that virtual
encoded data is transferred to the decoding buffer memory following the
transfer of first-encoded data to the decoding buffer memory,
the data occupancy when last data in the first-encoded data is decoded is
calculated as a final buffer occupancy Be,
the data occupancy when the encoding process producing second encoded data
is begun is an initial buffer occupancy Bi where the initial buffer
occupancy Bi is less than the final buffer occupancy Be, and
the allocated code size is defined based on the change in the data
occupancy.
2. An encoding method for producing specific encoded data comprising:
calculating the data occupancy of a decoding buffer memory of a particular
size that is used when decoding the encoded data during reproduction,
defining the allocated code size of a particular period based on the
calculation result, and
compression coding the signal of a particular period to the allocated code
size,
wherein the data occupancy is calculated on the assumption that virtual
encoded data is transferred to the decoding buffer memory following the
transfer of first-encoded data to the decoding buffer memory,
the data occupancy when last data in the first-encoded data is decoded is
calculated as a final buffer occupancy Be,
the data occupancy when the encoding process producing second-encoded data
is begun is an initial buffer occupancy Bi,
the allocated code size is defined based on the change in the data
occupancy, and
the allocated code size is defined such that the final buffer occupancy Be
of the first-encoded data is greater than a particular size Bt where
Bt>Bi.
3. An encoding method for producing specific encoded data comprising:
calculating the data occupancy of a decoding buffer memory of a particular
size that is used when decoding the encoded data during reproduction,
defining the allocated code size of particular period based on the
calculation result, and
compression coding the signal of a particular period to the allocated code
size,
wherein the data occupancy when the encoding process producing each of the
encoded data is begun is an initial buffer occupancy Bi,
the data occupancy is calculated on the assumption that virtual encoded
data is transferred to the decoding buffer memory following the transfer
of the encoded data to the decoding buffer memory,
the data occupancy when last data in the encoded data is decoded is
calculated as a final buffer occupancy Be,
the allocated code size is defined based on the change in the data
occupancy, and is defined such that the final buffer occupancy Be is
greater than a particular Bt where Bt>Bi.
4. An encoding method according to any of claims 1 to 3 whereby the
allocated code size is defined such that the data occupancy is greater
than a particular minimum occupancy B1.
5. An encoding method according to any of claims 1 to 3 whereby the encoded
data is input to the decoding buffer memory at a variable transfer rate.
6. An encoding method according to any of claims 1 to 3 whereby when the
encoded data is input to the decoding buffer memory, the data is
transferred intermittently.
7. An encoding method according to any of claims 1 to claim 3 whereby the
data occupancy is controlled to always be less than a particular maximum
occupancy Bmax.
8. An encoding apparatus for compression coding a signal to produce encoded
data, said apparatus comprising:
a code size regulator for defining the allocated code size of a particular
period,
a compression coding controller for producing an encoded data signal and
controlling the code size of the encoded signal to reduce the difference
between the allocated code size and a generated code size of the encoded
data, and
a data occupancy calculator for calculating the data occupancy of a
decoding buffer memory of a particular size that is used when decoding the
encoded data during reproduction, wherein the data occupancy calculator
calculates the data occupancy on the assumption that virtual encoded data
is transferred to the decoding buffer memory following the transfer of
first-encoded data to the decoding buffer memory,
the data occupancy calculator calculates the data occupancy when the last
data in the first-encoded data is decoded as a final buffer occupancy Be,
the data occupancy calculator sets the data occupancy when the encoding
process producing second encoded data is begun to an initial buffer
occupancy Bi where the initial buffer occupancy Bi is less than the final
buffer occupancy Be, and
the code size regulator defines the allocated code size based on the change
in the data occupancy.
9. An encoding apparatus for compression coding a signal to produce encoded
data, said apparatus comprising:
a code size regulator for defining the allocated code size of a particular
period,
a compression coding controller for producing an encoded data signal and
controlling the code size of the encoded signal to reduce the difference
between the allocated code size and a generated code size of the encoded
data, and
a data occupancy calculator for calculating the data occupancy of a
decoding buffer memory of a particular size that is used when decoding the
encoded data during reproduction, wherein the data occupancy calculator
calculates the data occupancy on the assumption that virtual encoded data
is transferred to the decoding buffer memory following the transfer of
first-encoded data to the decoding buffer memory,
calculates the data occupancy when the last data in the first.sub.--
encoded data is decoded as a final buffer occupancy Be,
sets the data occupancy when the encoding process producing second encoded
data is begun to an initial buffer occupancy Bi,
defines the allocated code size based on the change in the data occupancy,
and
the code size regulator defines the allocated code size based on the data
occupancy such that the final buffer occupancy Be of the first-encoded
data is greater than a particular size Bt where Bt>Bi.
10. An encoding apparatus for compression coding a signal to produce
encoded data, said apparatus comprising:
a code size regulator for defining the allocated code size of a particular
period,
a compression coding controller for producing an encoded data signal and
controlling the code size of the encoded signal to reduce the difference
between the allocated code size and a generated code size of the encoded
data, and
a data occupancy calculator for calculating the data occupancy of a
decoding buffer memory of a particular size that is used when decoding the
encoded data during reproduction,
wherein the data occupancy calculator
sets the data occupancy when the encoding process producing each of the
encoded data is begun to an initial buffer occupancy Bi, and
calculates the data occupancy on the assumption that virtual encoded data
is transferred to the decoding buffer memory following the transfer of the
encoded data to the decoding buffer memory,
the code size regulator defines the allocated code size based on the data
occupancy such that a final buffer occupancy Be of the encoded data is
greater than a particular size Bt where Bt>Bi.
11. An encoding apparatus according to any of claims 8 to 10 wherein the
allocated code size is defined such that the data occupancy is greater
than a particular minimum occupancy B1.
12. An encoding apparatus according to any of claims 8 to 10 wherein the
encoded data is input to the decoding buffer memory at a variable transfer
rate.
13. An encoding apparatus according to any of claims 8 to 10 wherein when
the encoded data is input to the decoding buffer memory, the data is
transferred intermittently.
14. An encoding apparatus according to any of to claims 8 to 10 wherein the
data occupancy is controlled to be less than a particular maximum
occupancy Bmax.
15. A recording method for recording to a recording medium encoded data
processed according to the data occupancy of a decoding buffer memory of a
particular size that is used when decoding the encoded data during
reproduction, said method comprising:
determining that a data occupancy when last data in first-encoded data is
decoded is a final buffer occupancy Be where it is assumed that virtual
encoded data is transferred to the decoding buffer memory following the
transfer of the first-encoded data to the decoding buffer memory,
determining that a data occupancy at the start of second-encoded data is an
initial buffer occupancy Bi where the initial buffer occupancy Bi is less
than the final buffer occupancy Be, and
processing and recording the encoded data according to the determined data
occupancy of the decoding buffer memory.
16. A recording method according to claim 15 whereby decoding buffer memory
input time information of the encoded data is recorded to interrupt data
transfer to the buffer memory for a particular period T (T>O) when the
first-encoded data and second-encoded data are transferred to the decoding
buffer memory,
where period T is defined by the final buffer occupancy Be of the
first-encoded data and the initial buffer occupancy Bi of the
second-encoded data.
17. A recording method according to claim 16 where the period T is defined
as ((Be-Bi)/BR) where the data transfer rate to the decoding buffer memory
is BR.
18. A recording method according to claim 15 whereby data of a particular
pattern of a particular data size defined as (Be-Bi) is inserted and
recorded to the first-encoded data.
19. A recording medium including encoded data processed according to the
data occupancy of a decoding buffer memory of a particular size that is
used when decoding the encoded data during reproduction by a recording
medium reproduction device, said recording medium comprising:
a plurality of data blocks,
control data for controlling a reproduction order of the plurality of data
blocks, said control data including a seamless reproduction flag which
indicates encoded data to be seamlessly reproduced, and
encoded data recorded such that the data occupancy when last data in
first-encoded data is decoded is a final buffer occupancy Be where it is
assumed that virtual encoded data is transferred to the decoding buffer
memory following the transfer of the first-encoded data to the decoding
buffer memory, and the data occupancy at the start of decoding of
second-encoded data is an initial buffer occupancy Bi where the initial
buffer occupancy Bi is less than the final buffer occupancy Be.
20. A recording medium according to claim 19 wherein the recording medium
is an optical disk.
21. A recording medium according to claim 19 wherein decoding buffer memory
input time information of the data is recorded to interrupt data transfer
to the decoding buffer memory for a particular period T (T>O) when
first-encoded data and second-encoded data are transferred to the decoding
buffer memory,
where period T is defined by the final occupancy Be of the first-encoded
data and the initial buffer occupancy Bi of the second-encoded data.
22. A recording medium according to claim 21 wherein period T is defined as
((Be-Bi)/BR) where the data transfer rate to the decoding buffer memory is
BR.
23. A recording medium according to claim 19 wherein data of a particular
pattern of a particular data size defined as (Be-Bi) is inserted and
recorded to the first-encoded data.
24. A reproduction method for reproducing data from a recording medium
having recorded thereon encoded data processed according to the data
occupancy of a decoding buffer memory of a particular size that is used
when decoding the encoded data during reproduction, said method
comprising:
transferring encoded data to the decoding buffer memory such that the data
occupancy when last data in first-encoded data is decoded is a final
buffer occupancy Be where it is assumed that virtual encoded data is
transferred to the decoding buffer memory following the transfer of the
first-encoded data to the decoding buffer memory, and
the data occupancy at the start of decoding second-encoded data is an
initial buffer occupancy Bi where the initial buffer occupancy Bi is less
than the final buffer occupancy Be, and
reproducing the encoded data.
25. A reproduction method according to claim 24 whereby data transfer to
the decoding buffer memory is interrupted for a particular period T (T>O)
when first-encoded data and second-encoded data are transferred to the
decoding buffer memory,
where period T is defined by the final buffer occupancy Be of the
first-encoded data and the initial buffer occupancy Bi of the
second-encoded data.
26. A reproduction method according to claim 25 wherein period T is defined
as ((Be-Bi)/BR) where the data transfer rate to the decoding buffer memory
is BR.
27. A reproduction method according to claim 24 whereby the encoded data is
in put to the decoding buffer memory at a variable transfer rate.
28. A reproduction method according to claim 24 whereby the encoded data is
input intermittently to the decoding buffer memory.
29. A reproduction method according to claim 24 whereby transfer of the
encoded data to the decoding buffer memory is controlled so that the data
occupancy is always less than a particular maximum occupancy Bmax. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and apparatus for system encoding
bitstreams for seamless connection and, more specifically, to bitstreams
for use in an authoring system for variously processing a data bitstream
comprising the video data, audio data, and sub-picture data constituting
each of plural program titles containing related video data, audio data,
and sub-picture data content to generate a bitstream from which a new
title containing the content desired by the user can be reproduced, and
efficiently recording and reproducing the generated bitstream using a
particular recording medium.
2. Description of the Prior Art
Authoring systems used to produce program titles comprising related video
data, audio data, and sub-picture data by digitally processing, for
example, multimedia data comprising video, audio, and sub-picture data
recorded to laser disk or video CD formats are currently available.
Systems using Video-CDs in particular are able to record video data to a CD
format disk, which was originally designed with an approximately 600 MB
recording capacity for storing digital audio data only, by using such high
efficiency video compression techniques as MPEG. As a result of the
increased effective recording capacity achieved using data compression
techniques, karaoke titles and other conventional laser disk applications
are gradually being transferred to the video CD format.
Users today expect both sophisticated title content and high reproduction
quality. To meet these expectations, each title must be composed from
bitstreams with an increasingly deep hierarchical structure. The data size
of multimedia titles written with bitstreams having such deep hierarchical
structures, however, is ten or more times greater than the data size of
less complex titles. The need to edit small image (title) details also
makes it necessary to process and control the bitstream using low order
hierarchical data units.
It is therefore necessary to develop and prove a bitstream structure and an
advanced digital processing method including both recording and
reproduction capabilities whereby a large volume, multiple level
hierarchical digital bitstream can be efficiently controlled at each level
of the hierarchy. Also needed are an apparatus for executing this digital
processing method, and a recording media to which the bitstream digitally
processed by the apparatus can be efficiently recorded for storage and
from which the recorded information can be quickly reproduced.
Increasing the storage capacity of conventional optical disks has been
widely researched to address the recording medium aspect of this problem.
One way to increase the storage capacity of the optical disk is to reduce
the spot diameter D of the optical (laser) beam. If the wavelength of the
laser beam is 1 and the aperture of the objective lens is NA, then the
spot diameter D is proportional to 1/NA, and the storage capacity can be
efficiently improved by decreasing 1 and increasing NA.
As described, for example, in U.S. Pat. No. 5,235,581, however, coma caused
by a relative tilt between the disk surface and the optical axis of the
laser beam (hereafter "tilt") increases when a large aperture (high NA)
lens is used. To prevent tilt-induced coma, the transparent substrate must
be made very thin. The problem is that the mechanical strength of the disk
is low when the transparent substrate is very thin.
MPEG1, the conventional method of recording and reproducing video, audio,
and graphic signal data, has also been replaced by the more robust MPEG2
method, which can transfer large data volumes at a higher rate. It should
be noted that the compression method and data format of the MPEG2 standard
differ somewhat from those of MPEG1. The specific content of and
differences between MPEG1 and MPEG2 are described in detail in the
ISO-11172 and ISO-13818 MPEG standards, and further description thereof is
omitted below.
Note, however, that while the structure of the encoded video stream is
defined in the MPEG2 specification, the hierarchical structure of the
system stream and the method of processing lower hierarchical levels are
not defined.
As described above, it is therefore not possible in a conventional
authoring system to process a large data stream containing sufficient
information to satisfy many different user requirements. Moreover, even if
such a processing method were available, the processed data recorded
thereto cannot be repeatedly used to reduce data redundancy because there
is no large capacity recording medium currently available that can
efficiently record and reproduce high volume bitstreams such as described
above.
More specifically, particular significant hardware and software
requirements must be satisfied in order to process a bitstream using a
data unit smaller than the title. These specific hardware requirements
include significantly increasing the storage capacity of the recording
medium and increasing the speed of digital processing; software
requirements include inventing an advanced digital processing method
including a sophisticated data structure.
Therefore, the object of the present invention is to provide an effective
authoring system for controlling a multimedia data bitstream with advanced
hardware and software requirements using a data unit smaller than the
title to better address advanced user requirements.
To share data between plural titles and thereby efficiently utilize optical
disk capacity, multi-scene control whereby scene data common to plural
titles and the desired scenes on the same time-base from within
multi-scene periods containing plural scenes unique to particular
reproduction paths can be freely selected and reproduced is desirable.
However, when plural scenes unique to a reproduction path within the
multi-scene period are arranged on the same time-base, the scene data must
be contiguous. Unselected multi-scene data is therefore unavoidably
inserted between the selected common scene data and the selected
multi-scene data. The problem this creates when reproducing multi-scene
data is that reproduction is interrupted by this unselected scene data.
A further problem can be expected when the multi-scene data is multi-angle
scene data, i.e., scene data showing substantially the same subject from
different angles. In the case of a live sports broadcast, this multi-angle
scene data may be obtained by recording a baseball batter, for example,
with cameras in different locations. The video signals from these plural
angles are then combined in predefined data units to obtain a single
title. Specifically how these plural video streams will be connected and
reproduced, however, cannot be determined during the encoding process. As
a result, the behavior of the decoder video buffer, specifically the data
accumulation state of the video buffer during the decoding process, cannot
be determined during the encoding process. As a result, a video buffer
overflow or underflow state may occur during decoding. Even at one-to-one
connections between common scenes (system streams), the behavior of the
decoder video buffer cannot be determined during encoding.
When variable length coding is used for the coding process, the process
must always proceed in a time-base linear fashion. This makes it necessary
to control the sequence of the coding process, and limits the flexibility
of the title production process. In addition, there are cases in which the
final buffer occupancy during first video stream encoding exceeds the
initial buffer occupancy of the second video stream. In such cases, a
decoding buffer overflow may occur at some indeterminate time during the
coding process.
When MPEG coding or a similar variable length coding process is used during
the coding process generating the video stream, the coded data quantity is
only known once the coding process is completed. This is because the
coding length used is determined according to the amount of information in
the video data, i.e., the spatial complexity or time-base complexity of
the video data, and the preceding code state, and the code length is then
determined. Because it is therefore difficult to accurately limit the
encoded data size to a specific, predetermined size, it is difficult to
accurately specify the final buffer occupancy. Particularly when the
encoded data volume is allocated and the coding process is accomplished
according to the amount of information in the video stream, the allocated
data volume will obviously vary if the amount of information in the video
stream changes, and the change in video buffer occupancy will vary. It is
therefore difficult to assure that the final decode video buffer occupancy
is the same with each of plural video streams.
Therefore, the object of the present invention is to provide a coding
method and coding apparatus, a recording method and recording apparatus,
and a reproduction method and reproduction apparatus whereby plural
independently coded video streams can be freely connected and reproduced
without causing a video buffer overflow or underflow state.
A further object of the present invention is to provide a coding method and
coding apparatus, a recording method and recording apparatus, and a
reproduction method and reproduction apparatus whereby the need for the
coding process to proceed in a linear time-base fashion to obtain each
video stream is eliminated, the processing time can be shortened by means
of parallel coding processes, and process control can be simplified when
plural video streams are connected to obtain a single video stream.
A further object of the present invention is to provide a coding method and
coding apparatus, a recording method and recording apparatus, and a
reproduction method and reproduction apparatus whereby video streams from
plural reproduction paths are coded to a multi-scene period from which the
user can select a particular reproduction path during reproduction, and
the desired video streams from the multi-scene period containing plural
selectable video streams (reproduction paths) can then be individually
reproduced and contiguously presented as a single video stream without
causing a video buffer overflow or underflow state during the decoding
(reproduction) process.
The present application is based upon Japanese Patent Application No.
7-252736 and 8-041582, which were filed on Sep. 29, 1995 and Feb. 28,
1996, respectively, the entire contents of which are expressly
incorporated by reference herein.
SUMMARY OF THE INVENTION
The present invention has been developed with a view to substantially
solving the above described disadvantages and has for its essential object
to provide an interleaving method for generating a bitstream.
In order to achieve the aforementioned objective, an encoding method for
producing specific encoded data comprises steps of: calculating the data
occupancy of a decoding buffer memory of a particular size that is used
when decoding the encoded data during reproduction, defining the allocated
code size of a particular period based on the calculation result, and
compression coding the signal of a particular period to the allocated code
size, wherein the data occupancy is calculated on the assumption that
virtual encoded data is transferred to the decoding buffer memory
following the transfer of first-encoded data to the decoding buffer
memory, the data occupancy when last data in the first encoded data is
decoded is calculated as a final buffer occupancy Be, the data occupancy
when the encoding process producing second encoded data is begun is an
initial buffer occupancy Bi where the initial buffer occupancy Bi is less
than the final buffer occupancy Be, and the allocated code size is defined
based on the change in the data occupancy.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects and features of the present invention will become
clear from the following detailed description taken in conjunction with
the preferred embodiments thereof with reference to the accompanying
drawings throughout which like parts are designated by like reference
numerals, and in which:
FIG. 1 is a graph schematically showing a structure of multi media bit
stream according to the present invention,
FIG. 2 is a block diagram showing an authoring encoder according to the
present invention,
FIG. 3 is a block diagram showing an authoring decoder according to the
present invention,
FIG. 4 is a side view of an optical disk storing the multi media bit stream
of FIG. 1,
FIG. 5 is an enlarged view showing a portion confined by a circle of FIG.
4,
FIG. 6 is an enlarged view showing a portion confined by a circle of FIG.
5,
FIG. 7 is a side view showing a variation of the optical disk of FIG. 4,
FIG. 8 is a side view showing another variation of the optical disk of FIG.
4,
FIG. 9 is a plan view showing one example of track path formed on the
recording surface of the optical disk of FIG. 4,
FIG. 10 is a plan view showing another example of track path formed on the
recording surface of the optical disk of FIG. 4,
FIG. 11 is a diagonal view schematically showing one example of a track
path pattern formed on the optical disk of FIG. 7,
FIG. 12 is a plan view showing another example of track path formed on the
recording surface of the optical disk of FIG. 7,
FIG. 13 is a diagonal view schematically showing one example of a track
path pattern formed on the optical disk of FIG. 8,
FIG. 14 is a plan view showing another example of track path formed on the
recording surface of the optical disk of FIG. 8,
FIG. 15 is a graph in assistance of explaining a concept of parental
control according to the present invention,
FIG. 16 is a graph schematically showing the structure of multimedia bit
stream for use in Digital Video Disk system according to the present
invention,
FIG. 17 is a graph schematically showing the encoded video stream according
to the present invention,
FIG. 18 is a graph schematically showing an internal structure of a video
zone of FIG. 16.
FIG. 19 is a graph schematically showing the stream management information
according to the present invention,
FIG. 20 is a graph schematically showing the structure the navigation pack
NV of FIG. 17,
FIG. 21 is a graph is assistance of explaining a concept of parental lock
playback control according to the present invention,
FIG. 22 is a graph schematically showing the data structure used in a
digital video disk system according to the present invention,
FIG. 23 is a graph in assistance of explaining a concept of Multi-angle
scene control according to the present invention,
FIG. 24 is a graph in assistance of explaining a concept of multi scene
data connection,
FIG. 25 is a block diagram showing a DVD encoder according to the present
invention,
FIG. 26 is a block diagram showing a DVD decoder according to the present
invention,
FIG. 27 is a graph schematically showing an encoding information table
generated by the encoding system controller of FIG. 25,
FIG. 28 is a graph schematically showing an encoding information table,
FIG. 29 is a graph schematically showing encoding parameters used by the
video encoder of FIG. 25,
FIG. 30 is a graph schematically showing an example of the contents of the
program chain information according to the present invention,
FIG. 31 is a graph schematically showing another example of the contents of
the program chain information according to the present invention,
FIG. 32A, 32B, 32C, and 32D are graphs in assistance of explaining the
changes in the accumulated video data volume Vdv in the video buffer in
the various occasions,
FIG. 33 is a graph in assistance of explaining a concept of multi-angle
scene control according to the present in invention,
FIG. 34 is a flow chart, formed by FIGS. 34A and 34B, showing an operation
of the DVD encoder of FIG. 25,
FIG. 35 is a flow chart showing details of the encode parameter production
sub-routine of FIG. 34,
FIG. 36 is a flow chart showing the details of the VOB data setting routine
of FIG. 35,
FIG. 37 is a flow chart showing the encode parameters generating operation
for a seamless switching,
FIG. 38 is a flow chart showing the encode parameters generating operation
for a system stream,
FIG. 39 is a graph in assistance of explaining a change in the accumulated
video data volume Vdv in the video buffer 2600 during intermittent data
transfer when encoded video stream SS1 and encoded video stream SS2 are
connected,
FIG. 40 is a graph in assistance of explaining the data transfer of the
encoded video stream to the video buffer starting at time Ti,
FIG. 41 is a graph in assistance of explaining the change in the
accumulated video data volume of the video buffer when the encoded video
stream is transferred to the video buffer and decoded in the DVD decoder,
FIG. 42 is a graph in assistance of explaining the change in the
accumulated video data volume of the video buffer when two encoded video
streams are connected,
FIG. 43 is a graph in assistance of explaining the method of selecting and
reproducing one scene from plural scenes in a multi-scene period,
FIG. 44 is a graph in assistance of explaining a time-base relationship
between the component audio and video streams,
FIG. 45 is a graph in assistance of explaining a method of moving part of
the video stream or audio stream using the system stream encoding method,
FIG. 46 is a graph in assistance of explaining the change in the
accumulated video data volume in the video buffer during intermittent data
transfer,
FIGS. 47 and 48 are graphs showing a decoding information table produced by
the decoding system controller of FIG. 26,
FIG. 49 is a flow chart showing the operation of the DVD decoder DCD of
FIG. 26,
FIG. 50 is a flow chart showing details of the reproduction extracted PGC
routing of FIG. 49,
FIG. 51 is a flow chart showing details of the decoding data process of
FIG. 50, performed by the stream buffer, is shown,
FIG. 52 is a flow chart showing details of the decoder synchronization
process of FIG. 51,
FIG. 53 is a block diagram showing a video encoder of the DVD encoder ECD
of FIG. 25,
FIG. 54 is a flow chart showing an operation of the decoding buffer
occupation calculator of FIG. 53,
FIG. 55 is a block diagram showing a construction of the decoding buffer
occupation calculator of FIG. 53,
FIG. 56 is a flow chart showing an operation of the decoding buffer
occupation calculator of FIG. 3,
FIG. 57 is a block diagram showing a modification of the decoding buffer
occupation calculator of FIG. 55,
FIG. 58 is a flow chart showing a modified operation of the decoding buffer
occupation calculator of FIG. 56,
FIG. 59 is a block diagram of the decoding buffer occupation calculator
executing the flow chart shown in FIG. 58,
FIG. 60 is a graph in assistance of explaining a bitstream reproduction
method for connecting and reproducing the encoded video streams,
FIG. 61 is a graph in assistance of a bitstream production method,
FIG. 62 is on a plan view of a digital video disk showing a structure of
the data recorded thereon,
FIGS. 63A and 63B are graphs showing the change over time in the
accumulated video data volume in the video buffer during encoded video
stream decoding,
FIG. 64 is a flow chart showing the encode parameters generating operation
for a system stream containing a single scene,
FIG. 65 is a graph schematically showing an actual arrangement of data
blocks recorded to a data recording track on a recording medium according
to the present invention,
FIG. 66 is a graph schematically showing contiguous block regions and
interleaved block regions array,
FIG. 67 is a graph schematically showing a content of a VTS title VOBS
(VTSTT.sub.-- VOBS) according to the present invention, and
FIG. 68 is a graph schematically showing an internal data structure of the
interleaved block regions according to the present invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
Data Structure of the Authoring System
The logic structure of the multimedia data bitstream processed using the
recording apparatus, recording medium, reproduction apparatus, and
authoring system according to the present invention is described first
below with reference to FIG. 1.
In this structure, one title refers to the combination of video and audio
data expressing program content recognized by a user for education,
entertainment, or other purpose. Referenced to a motion picture (movie),
one title may correspond to the content of an entire movie, or to just one
scene within the movie.
A video title set (VTS) comprises the bitstream data containing the
information for a specific number of titles. More specifically, each VTS
comprises the video, audio, and other reproduction data representing the
content of each title in the set, and control data for controlling the
content data.
The video zone VZ is the video data unit processed by the authoring system,
and comprises a specific number of video title sets. More specifically,
each video zone is a linear sequence of K+1 video title sets numbered VTS
#0-VTS #K where K is an integer value of zero or greater. One video title
set, preferably the first video title set VTS #0, is used as the video
manager describing the content information of the titles contained in each
video title set.
The multimedia bitstream MBS is the largest control unit of the multimedia
data bitstream handled by the authoring system of the present invention,
and comprises plural video zones VZ.
Authoring Encoder EC
A preferred embodiment of the authoring encoder EC according to the present
invention for generating a new multimedia bitstream MBS by re-encoding the
original multimedia bitstream MBS according to the scenario desired by the
user is shown in FIG. 2. Note that the original multimedia bitstream MBS
comprises a video stream St1 containing the video information, a
sub-picture stream St3 containing caption text and other auxiliary video
information, and the audio stream St5 containing the audio information.
The video and audio streams are the bitstreams containing the video and
audio information obtained from the source within a particular period of
time. The sub-picture stream is a bitstream containing momentary video
information relevant to a particular scene. The sub-picture data encoded
to a single scene may be captured to video memory and displayed
continuously from the video memory for plural scenes as may be necessary.
When this multimedia source data St1, St3, and St5 is obtained from a live
broadcast, the video and audio signals are supplied in real-time from a
video camera or other imaging source; when the multimedia source data is
reproduced from a video tape or other recording medium, the audio and
video signals are not real-time signals.
While the multimedia source stream is shown in FIG. 2 as comprising these
three source signals, this is for convenience only, and it should be noted
that the multimedia source stream may contain more than three types of
source signals, and may contain source data for different titles.
Multimedia source data with audio, video, and sub-picture data for plural
titles are referred to below as multi-title streams.
As shown in FIG. 2, the authoring encoder EC comprises a scenario editor
100, encoding system controller 200, video encoder 300, video stream
buffer 400, sub-picture encoder 500, sub-picture stream buffer 600, audio
encoder 700, audio stream buffer 800, system encoder 900, video zone
formatter 1300, recorder 1200, and recording medium M.
The video zone formatter 1300 comprises a video object (VOB) buffer,
formatter, and volume and file structure formatter (not shown).
The bitstream encoded by the authoring encoder EC of the present embodiment
is recorded by way of example only to an optical disk.
The scenario editor 100 of the authoring encoder EC outputs the scenario
data, i.e., the user-defined editing instructions. The scenario data
controls editing the corresponding parts of the multimedia bitstream MBS
according to the user's manipulation of the video, sub-picture, and audio
components of the original multimedia title. This scenario editor 100
preferably comprises a display, speaker(s), keyboard, CPU, and source
stream buffer. The scenario editor 100 is connected to an external
multimedia bitstream source from which the multimedia source data St1,
St3, and St5 are supplied.
The user is thus able to reproduce the video and audio components of the
multimedia source data using the display and speaker to confirm the
content of the generated title. The user is then able to edit the title
content according to the desired scenario using the keyboard, mouse, and
other command input devices while confirming the content of the title on
the display and speakers. The result of this multimedia data manipulation
is the scenario data St7.
The scenario data St7 is basically a set of instructions describing what
source data is selected from all or a subset of the source data containing
plural titles within a defined time period, and how the selected source
data is reassembled to reproduce the scenario (sequence) intended by the
user. Based on the instructions received through the keyboard or other
control device, the CPU codes the position, length, and the relative
time-based positions of the edited parts of the respective multimedia
source data streams St1, St3, and St5 to generate the scenario data St7.
The source stream buffer has a specific capacity, and is used to delay the
multimedia source data streams St1, St3, and St5 a known time Td and then
output streams St1, St3, and St5.
This delay is required for synchronization with the editor encoding
process. More specifically, when data encoding and user generation of
scenario data St7 are executed simultaneously, i.e., when encoding
immediately follows editing, time Td is required to determine the content
of the multimedia source data editing process based on the scenario data
St7 as will be described further below. As a result, the multimedia source
data must be delayed by time Td to synchronize the editing process during
the actual encoding operation. Because this delay time Td is limited to
the time required to synchronize the operation of the various system
components in the case of sequential editing as described above, the
source stream buffer is normally achieved by means of a high speed storage
medium such as semiconductor memory.
During batch editing in which all multimedia source data is encoded at once
("batch encoded") after scenario data St7 is generated for the complete
title, delay time Td must be long enough to process the complete title or
longer. In this case, the source stream buffer may be a low speed, high
capacity storage medium such as video tape, magnetic disk, or optical
disk.
The structure (type) of media used for the source stream buffer may
therefore be determined according to the delay time Td required and the
allowable manufacturing cost.
The encoding system controller 200 is connected to the scenario editor 100
and receives the scenario data St7 therefrom. Based on the time-base
position and length information of the edit segment contained in the
scenario data St7, the encoding system controller 200 generates the
encoding parameter signals St9, St11, and St13 for encoding the edit
segment of the multimedia source data. The encoding signals St9, St11, and
St13 supply the parameters used for video, sub-picture, and audio
encoding, including the encoding start and end timing. Note that
multimedia source data St1, St3, and St5 are output after delay time Td by
the source stream buffer, and are therefore synchronized to encoding
parameter signals St9, St11, and St13.
More specifically, encoding parameter signal St9 is the video encoding
signal specifying the encoding timing of video stream St1 to extract the
encoding segment from the video stream St1 and generate the video encoding
unit. Encoding parameter signal St11 is likewise the sub-picture stream
encoding signal used to generate the sub-picture encoding unit by
specifying the encoding timing for sub-picture stream St3. Encoding
parameter signal St13 is the audio encoding signal used to generate the
audio encoding unit by specifying the encoding timing for audio stream
St5.
Based on the time-base relationship between the encoding segments of
streams St1, St3, and St5 in the multimedia source data contained in
scenario data St7, the encoding system controller 200 generates the timing
signals St21, St23, and St25 arranging the encoded multimedia- | | |
