JPH11346341A - Optical disk and its recording device and method and reproducing device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To record two or more video data on an optical disk apparently as one video data by recording one or more AV streams constituted of two or more video data, and synthesizing and recording two or more video data in the AV streams on a spatial coordinate axis. SOLUTION: The video data of an input 1 and an input 2 are reduced into video data by thinning-out each horizontal resolution into half, and those two video data are synthesized. At that time, the video data of the input 1 and the video data of the input 2 are respectively stored in the left half part and right half part of the synthesized video data. Then, the audio data of the input 1 and the input 2 are synthesized as channels ch1 and ch2. Then, the video data and audio data synthesized into one stream are respectively encoded, multiplexed into an MPEG system stream, and recorded in a DVD-RAM disk.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a readable / writable optical disk, and a recording apparatus, a recording method, a reproducing apparatus, and a reproducing method thereof. In particular, the present invention relates to an optical disk on which multimedia data in which a plurality of moving image data and audio data are simultaneously recorded is recorded, and a recording apparatus, a recording method, a reproducing apparatus, and a reproducing method thereof.

[0002]

2. Description of the Related Art In the field of rewritable optical disks, the upper limit of which is about 650 MB, a phase change disk DVD-RAM having a capacity of several GB has appeared. Digital A
DVD-RAM is expected not only as a computer application but also as a recording / playback medium in AV, in conjunction with the practical use of MPEG (MPEG2) which is a coding standard of V data. In other words, it is expected to spread as a medium that replaces the magnetic tape, which is a conventional typical AV recording medium.

(Description of DVD-RAM) In recent years, the density of rewritable optical disks has been increased, and not only computer data and audio data but also image data can be recorded.

For example, a guide groove on an uneven surface is conventionally formed on a signal recording surface of an optical disk.

Conventionally, signals were recorded only on the convex or concave portions. However, signals can be recorded on both convex and concave portions by the land group recording method. As a result, the recording density was approximately doubled (see, for example, JP-A-8-7282).

Further, a zone CLV system which simplifies the control of the CLV system (constant linear velocity recording) effective for improving the recording density and facilitates its practical use has been devised and put into practical use (for example, Japanese Patent Laid-Open No. -93873).

[0007] It is a major task in the future how to record AV data including image data using these optical disks aiming at increasing the capacity and to realize performances and new functions that greatly exceed conventional AV equipment.

With the advent of such a large-capacity and rewritable optical disk, it is conceivable that AV recording and reproduction will be mainly performed by optical disks instead of conventional tapes. The transition of recording media from tape to disk has various effects on the functions and performance of AV equipment.

[0009] The greatest feature in the transition to a disk is a significant improvement in random access performance. In the case of random access to the tape, it usually takes several minutes to rewind one tape. This is orders of magnitude slower than the seek time (several tens of ms or less) in optical disk media. Thus, tape cannot be a random access device in practice.

With such random access performance, distributed recording of AV data, which was impossible with a conventional tape, has become possible with an optical disk.

FIG. 1 is a block diagram of a drive device of a DVD recorder. In the figure, reference numeral 11 denotes an optical pickup for reading data from a disk, and 12 denotes an ECC (error c).
and 13 is a track buffer, 14 is a switch for switching between input and output to and from the track buffer, 15 is an encoder, 16 is a decoder, and 17 is an enlarged view of the disk.

As shown in FIG. 17, data is recorded on a DVD-RAM disk with 1 sector = 2 KB as a minimum unit. Also, assuming that 16 sectors = 1 ECC block,
The ECC processing unit 12 performs an error correction process.

The track buffer shown in FIG.
A buffer for recording AV data at a variable bit rate in order to more efficiently record AV data on a RAM disk. While the read / write rate to the DVD-RAM (Va in the figure) is a fixed rate, the bit rate (Vb in the figure) of the AV data changes according to the complexity of the content (image in the case of video) Therefore, it is a buffer for absorbing the difference between the bit rates. For example,
This is unnecessary when the AV data is set at a fixed bit rate like a video CD.

If the track buffer 13 is used more effectively, it is possible to arrange AV data discretely on a disk. This will be described with reference to FIG.

FIG. 2A is a diagram showing an address space on a disk. As shown in FIG. 2A, when AV data is recorded separately in a continuous area of [a1, a2] and a continuous area of [a3, a4], while the seek is performed from a2 to a3, the track is recorded. By supplying the data stored in the buffer to the decoder section, continuous reproduction of AV data becomes possible. FIG. 2B shows the state at this time.

The AV data whose reading has been started from a1 starts to be input to the track buffer and output from the track buffer at time t1, and the input rate (Va) to the track buffer and the output rate (Vb) from the track buffer. The data is accumulated in the track buffer by the rate difference (Va-Vb). This state is a
2 (time t2). Assuming that the amount of data stored in the track buffer during this time is B (t2), B (t2) stored in the track buffer is consumed and supplied to the decoder until time t3 when reading of a3 can be started. Good.

In other words, if the data amount ([a1, a2]) to be read before the seek is at least a certain amount, continuous supply of AV data is possible even when a seek occurs.

In this embodiment, an example in which data is read from a DVD-RAM, that is, in the case of reproduction, has been described.
-Writing data to the RAM, that is, recording, can be similarly considered.

As described above, in a DVD-RAM, continuous reproduction / recording is possible even if AV data is dispersedly recorded on a disk as long as data of a predetermined amount or more is continuously recorded.

(Explanation of MPEG) Next, the AV data will be described.

As described above, the AV data to be recorded on the DVD-RAM is MPEG (ISO / IEC13818).
Use international standards called.

Even a DVD-RAM having a large capacity of several GB cannot be said to have a sufficient capacity to record uncompressed digital AV data as it is. Therefore, a method of compressing and recording AV data is required.
MPEG (ISO / IE) is used as a compression method for AV data.
C13818) has become widespread in the world. Recent L
MPEG technology (decompression / decompression)
Compression LSI) has come into practical use. This has enabled MPEG expansion / compression in DVD recorders.

MPEG has the following two main features to realize highly efficient data compression.

First, in the compression of moving image data,
In addition to the conventional compression method using spatial frequency characteristics, a compression method using time correlation characteristics between frames has been introduced. In MPEG, each frame (also referred to as a picture in MPEG) is defined as an I picture (intra-frame coded picture), a P picture (picture using intra-frame coding and a reference relationship from the past), and a B picture (intra-frame coded picture). Data using a reference relationship from the past and the future).

FIG. 3 is a diagram showing the relationship among I, P, and B pictures. As shown in FIG. 3, the P picture refers to the closest I or P picture in the past, and the B picture refers to the closest I or P picture in the past and the future, respectively. Since the B picture refers to a future I or P picture as shown in FIG. 3, the display order of each picture (d
A phenomenon occurs in which the display order does not match the order of the compressed data.

The second feature of MPEG is that dynamic code amount allocation according to the complexity of an image can be performed on a picture basis. The MPEG decoder has an input buffer,
By storing data in this decoder buffer in advance, a large amount of code can be allocated to a complicated image that is difficult to compress.

The audio data used in the DVD-RAM can be selected from three types: MPEG audio for data compression, Dolby Digital (AC-3) and uncompressed LPCM. Dolby Digital and LPCM
Is a fixed bit rate, but MPEG audio is not as large as a video stream, but can be selected from several sizes in audio frame units.

Such AV data is multiplexed into one stream by a method called an MPEG system. FIG.
FIG. 1 is a diagram showing a configuration of an MPEG system. 41 is a pack header, 42 is a packet header, and 43 is a payload. The MPEG system has a hierarchical structure called a pack or a packet. The packet is a packet header 42
And a payload 43. The AV data is divided into appropriate sizes from the beginning and stored in the payload 43. The packet header 42 includes, as information of the AV data stored in the payload 43, an ID (stream ID) for identifying the stored data and 90k.
Hz, the decoding time DTS (Decoding Time) of the data contained in the payload expressed with the accuracy of Hz.
Stamp) and display time PTS (Present)
ation Time Stamp (DT when decoding and display are performed simultaneously like audio data)
S is omitted) is recorded. A pack is a unit that combines a plurality of packets. In the case of DVD-RAM,
Since one pack is used for each packet, the pack includes a pack header 41 and a packet (packet header 42).
And payload 43). The pack header has an SCR (Sy) indicating the time at which data in the pack is input to the decoder buffer with an accuracy of 27 MHz.
(Stem Clock Reference) is recorded.

Such an MPEG system stream is
In the VD-RAM, one pack is divided into one sector (= 2048).
Record as B).

Next, a decoder for decoding the above-described MPEG system stream will be described. FIG.
Decoder model of PEG system decoder (P-ST
D). STC 51 is a reference time in the decoder
(System Time Clock), 52 is a demultiplexer for decoding a system stream, that is, demultiplexing, 53 is an input buffer of a video decoder, 54
Is a video decoder, 55 is the I, P picture and B
A reorder buffer for temporarily storing I and P pictures in order to absorb the difference between the data order and the display order generated between pictures. Reference numeral 56 denotes a switch for adjusting the output order of I, P and B pictures in the reorder buffer. , 57 are input buffers of the audio decoder, and 58 is an audio decoder.

Such an MPEG system decoder processes the above-mentioned MPEG system stream as follows. When the time of the STC 51 matches the SCR described in the pack header, the demultiplexer 52 inputs the pack. The demultiplexer 52 decodes the stream ID in the packet header and transfers the data of the payload to the decoder buffer for each stream. Also, the PTS and DTS in the packet header are extracted. The video decoder 54 sets the time of the STC 51 and D
At the time when the TS matches, the picture data is taken out from the video buffer 53 and subjected to decoding processing, the I and P pictures are stored in the reorder buffer 55, and the B picture is displayed and output as it is. The switch 56 is connected to the video decoder 54
Are the I and P pictures decoded by
Tilt to the reorder buffer 55 side to reorder buffer 55
Is output, and in the case of a B picture, it is tilted to the video decoder 54 side. The audio decoder 58, like the video decoder 54,
At the time when the PTS coincides with the PTS (there is no DTS in the case of audio), the data for one audio frame is extracted from the audio buffer 57 and decoded.

(Explanation of MPEG Multistream) Next, an example in which a plurality of moving image data and audio data are simultaneously recorded in such an MPEG stream will be described. A specific example will be described using two video streams and two audio streams.

FIG. 6 shows a plurality of moving image data (video stream 1 and video stream 2) and a plurality of audio data (audio stream 1 and audio stream 2).
Are multiplexed into one MPEG system stream.

As described with reference to FIG. 4, each of the elementary streams is packed and packetized, and
It is multiplexed into a G system stream.

What is important here is that the MPEG system has a mechanism for accurately identifying an elementary stream stored in each packet (pack) as a stream ID in a packet header.

In the example of FIG. 6, the stream ID of the video stream 1 is 0xe0, the stream ID of the video stream 2 is 0xe1, the stream ID of the audio stream 1 is 0xc0, and the stream ID of the audio stream 2 is 0xc1.

By assigning different IDs in this way, it is possible to simultaneously record a plurality of moving image data and audio data in one MPEG system stream.

(Explanation of Simultaneous Recording on VTR)
A method of recording a plurality of programs using R will be described.

It goes without saying that there is no function for simultaneously recording a plurality of programs on a VTR (VHS standard).
For example, when it is desired to simultaneously record two dramas broadcast simultaneously on different channels from 9 o'clock at night, the user generally uses two VTRs to record.

[0040]

SUMMARY OF THE INVENTION The present invention solves the following problems which are hindered in maximizing the performance of a DVD-RAM expected as a next-generation AV recording medium described in the above prior art, and DV which is the largest and favorite application of possible large capacity optical disc DVD-RAM
This implements a D recorder. In particular, a DVD recorder capable of simultaneously recording a plurality of programs is realized.

The biggest problem in recording a plurality of programs simultaneously with a DVD recorder is that the M
It is said that PEG codecs are not well-equipped in the market. Indeed, recent advances in LSI technology have
Although the PEG codec has been put into practical use, the unit price of the MPEG codec, for example, is actually more than twice as large as that of a decoding-only LSI. Implementing multiple MPEG codecs for recording multiple programs is for consumer AV
Is impractical for DVD recorders,
This can be a major obstacle in promoting the spread of VD recorders.

For the above reasons, it is difficult to simultaneously include a plurality of video streams and a plurality of audio streams in one MPEG system stream as described in the conventional example.

Also, simultaneous recording of a plurality of programs using a plurality of devices, which has been performed by a user in a conventional VTR, is an unrealistic solution for a DVD recorder which is going to spread in the future. is there. Conversely, if a single DVD recorder enables simultaneous recording of a plurality of programs that could not be achieved with a conventional VTR, this can be a great advantage in promoting the spread of DVD recorders.

[0044]

According to a first aspect of the present invention, there is provided an optical disc on which at least one AV stream comprising at least two pieces of video data is recorded. The AV stream is an optical disk characterized in that the two or more pieces of video data are combined and recorded on a spatial coordinate axis.

According to a second aspect of the present invention, in the optical disk according to the first aspect, the two or more pieces of video data are divided and recorded in a horizontal direction on a space coordinate axis of the AV stream. Optical disk.

According to a third aspect of the present invention, in the optical disk according to the first aspect, the two or more pieces of video data are divided and recorded in a vertical direction on a space coordinate axis of the AV stream. Optical disk.

The invention according to claim 4 is the invention according to claims 1 to 3
2. The optical disc according to claim 1, wherein at least two or more audio data reproduced in synchronization with the two or more video data are recorded in the AV stream.

The invention according to claim 5 is the optical disc according to any one of claims 1 to 4, wherein management information on the AV stream is recorded, wherein the management information includes at least two pieces of video data. The optical disc is characterized by recording identification information indicating that it is configured.

The invention according to claim 6 is the optical disc according to any one of claims 1 to 5, wherein reproduction sequence information of the AV stream is recorded, wherein the reproduction sequence information includes one piece of video data and audio data from the AV stream. The optical disc is characterized by recording identification information for taking out data.

The invention according to claim 7 is the invention according to claims 1 to 6
An optical disc recording apparatus for recording an optical disc according to claim 1, further comprising at least two or more input units for inputting video data and audio data, wherein at least two or more video data and audio data input from said input unit are transmitted. A synthesizing unit for synthesizing one video data and audio data, an encoder unit for encoding the video data and audio data into an AV stream, a system control unit for generating management information of the AV stream, An optical disc recording apparatus comprising a drive for recording the AV stream management information on an optical disc.

The invention according to claim 8 is the optical disk recording apparatus according to claim 7, wherein the synthesizing unit reduces video data input from the at least two or more input units in a horizontal direction on a spatial coordinate axis. An optical disk recording apparatus comprising: an image reduction unit that performs at least two video data reduced on the spatial coordinate axis; and an image recording / combination unit that temporarily records the video data and outputs the combined video data. I have.

According to a ninth aspect of the present invention, in the optical disk recording apparatus according to the seventh aspect, the synthesizing unit reduces video data input from the at least two or more input units in a vertical direction on a spatial coordinate axis. An optical disk recording apparatus comprising: an image reduction unit that performs at least two video data reduced on the spatial coordinate axis; and an image recording / combination unit that temporarily records the video data and outputs the combined video data. I have.

The tenth aspect of the present invention is the first to sixth aspects.
An optical disc recording method for recording an optical disc according to any one of the preceding claims, comprising a first input step and a second input step of inputting video data and audio data, and synthesizing the video data and audio data into one video data and audio data. A synthesizing step, an encoding step of encoding the video data and the audio data into an AV stream, a system control step of generating management information of the AV stream, and recording of the AV stream and the AV stream management information on an optical disc An optical disk recording method characterized by comprising steps.

The invention according to claim 11 is the optical disk recording method according to claim 10, wherein the synthesizing step comprises:
An image reduction step of reducing video data input from the first input step and the second input step in a horizontal direction on a spatial coordinate axis, and at least two or more image data reduced on the spatial coordinate axis; An optical disk recording method characterized by comprising an image recording / combining step of temporarily recording and outputting as combined video data, respectively.

According to a twelfth aspect of the present invention, in the optical disk recording method according to the tenth aspect, the synthesizing step includes:
An image reduction step of vertically reducing video data input from the first input step and the second input step on a spatial coordinate axis, and at least two or more image data reduced on the spatial coordinate axis; An optical disk recording method characterized by comprising an image recording / combining step of temporarily recording and outputting as combined video data, respectively.

The invention according to claim 13 is the invention according to claims 1 to 6
An optical disc reproducing apparatus for reproducing an optical disc according to claim 1, wherein the drive reads an AV stream and AV stream management information from the optical disc, and a system control unit that determines whether the AV stream is a composite stream based on the AV stream management information. If the AV stream is a composite AV stream, a decoder unit that decodes only one audio channel and decodes video data in accordance with an instruction from the system control unit, and the AV stream is a composite AV stream An optical disk, comprising: an enlarging unit for extracting and enlarging a designated area on the spatial coordinate axis of the video data in accordance with an instruction of the system control unit; and an output unit for displaying and outputting the video data and audio data. As a playback device There.

According to a fourteenth aspect of the present invention, there is provided the first to sixth aspects.
An optical disc reproducing method for reproducing the optical disc according to the above, wherein a reading step of reading an AV stream and AV stream management information from the optical disc;
A system control step of judging whether or not the AV stream is a composite stream from the V stream management information; and, if the AV stream is a composite AV stream, only one audio channel according to the instruction of the system control unit. A decoding step of performing decoding and decoding of video data; and, if the AV stream is a composite AV stream, an expansion step of extracting and enlarging a designated area on the spatial coordinate axis of the video data in accordance with an instruction of the system control step; An optical disc reproducing method characterized by comprising an output step of displaying and outputting the video data and the audio data.

[0058]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described using a DVD recorder and a DVD-RAM as one embodiment of the present invention.

(Logic Configuration on DVD-RAM) First, the DV
The logical configuration on the D-RAM will be described with reference to FIG. FIG. 7A shows a data configuration on a disk viewed through a file system, and FIG. 7B shows a physical sector address on the disk.

A lead-in area is provided at the head of the physical sector address, and a reference signal necessary for stabilizing the servo, an identification signal with another medium, and the like are recorded.
Following the lead-in area is a data area. Logically valid data is recorded in this part. Finally, there is a lead-out area where reference signals similar to those in the lead-in area are recorded.

At the head of the data area, management information for a file system called volume information is recorded. The description of the file system is omitted because it has no direct relation to the contents of this patent.

By passing through the file system, FIG.
As shown in (a), the data in the disk can be handled as a directory or a file.

As shown in FIG. 7A, all data handled by the DVD recorder is VID immediately below the ROOT directory.
It is located under the EO_RT directory.

The file handled by the DVD recorder is roughly 2
One management information file and a plurality (at least one) of AV files are classified according to types.

(Management Information File) Next, the contents of the management information file will be described with reference to FIG.

The management information file is roughly divided into VOs
It is divided into a B table and a PGC table. VOB is an MPEG program stream, and PGC is V
This defines the playback order of the Cell using an arbitrary partial section (or all sections) in the OB as one logical playback unit. In other words, VOB is one unit having a meaning as MPEG, and PGC is one unit in which a player performs reproduction.

The VOB table contains the number of VOBs Numb
er_of_VOBs and each VOB information are recorded.
B information is the corresponding AV file name AV_File_Na
me, VOB identifier VOB_ID in the disc, AV
Start address in file VOB_Start_
Address, end address VO in AV file
B_End_Address, VOB playback time length VO
B_Playback_Time and stream attribute information VOB_Attribute.

Stream attribute information VOB_Attrib
ute, video stream attribute information Video_Att
library, audio stream attribute information Audi
o_Attribute, application identification information A
application_flag and manufacturer-specific information M
It is composed of annature_information.

The PGC table contains the number of PGCs Numb
er_of_Cells and respective PGC information are recorded.
GC information is the number of cells in PGC Number_of_
The cell information includes the corresponding VOB_ID, the reproduction start time Cell_Start_Time in the VOB, the reproduction time Cell_Playback_Time in the VOB, and the reproduction start address Cell_Start_Adder in the VOB.
ss, playback end address in VOB Cell_End
_Address, Cell attribute information Cell_Att
library.

As described above, the VOB table is
The PGC table has information indicating a stream attribute, and the PGC table has information indicating a playback sequence.

(AV File) Next, an AV file will be described with reference to FIG.

An AV file is composed of a plurality (at least one) of VOBs, and VOBs are continuously recorded in the AV file. The VOB in the AV file is managed by the VOB information of the management information file described above. The player first accesses the management information file, and
By reading the start address and end address of
Access to VOB becomes possible. In the VOB, Cell is defined as a logical reproduction unit. Cell
Is a partial playback section (or entire section) of the VOB, and can be freely set by the user. With this Cell,
Simple editing can be performed without actually operating the AV data. Like the VOB, access information to the Cell is managed in the Cell information in the management information file. The player can access the cell by first accessing the management information file and reading the start address and end address of the cell.

Since the address information of the cell is based on the VOB and the address information of the VOB is based on the AV file, the address information of the VOB is actually added to the address information of the cell, and the address information in the AV file is actually obtained. After calculating, the player accesses the AV file.

(Synthesized Stream) Next, a method of creating a synthesized stream will be described with reference to FIG.

In this embodiment, the original input data is
The description will be given as x480 video data and monaural audio data.

First, the video data of the input 1 and the video data of the input 2 are each obtained by thinning the horizontal resolution by half.
It is reduced to 52 × 480 video data. Next, these two video data are combined. At this time, the left half of the synthesized video data contains the video data of input 1 and the right half contains the video data of input 2.

Next, audio data is synthesized by using the audio data of input 1 as channel 1 (ch1) and the audio data of input 2 as channel 2 (ch2).

Next, the video data and the audio data synthesized into one stream are respectively encoded, and then multiplexed into an MPEG system stream. At this time, what is important is that audio data is encoded as a dual monaural stream. Depending on the encoding method, a difference between audio channels may be used, and it is meaningless to apply the method between two audio data having no correlation as in the present embodiment.

The MPEG system stream created as described above is recorded on a DVD-RAM disk.

Next, a method of reproducing the composite stream created as described above will be described. The MPEG system stream read from the DVD-RAM disc is separated (demultiplexed) and decompressed. At this time, of the audio data encoded as a dual monaural stream, only one audio data is decoded. The specification of the audio data (channel) to be decoded will be described later.

Next, a necessary portion (352 × 480 on the left side or 352 × 480 on the right side) is extracted from the expanded 704 × 480 video data and enlarged to a resolution of 704 × 480, and the enlarged video data and decoded audio data are output.

The reproduction of the composite stream is performed as described above. (Management Information of Synthetic Stream) Next, a method of managing the synthetic stream will be described.

The information necessary for managing the composite stream is the presence / absence of the composite stream and the behavior at the time of reproduction, that is, information for specifying video data and audio data to be reproduced in the composite stream. In the present embodiment, the existence of the combined stream is managed at the VOB level, and the behavior at the time of reproduction is managed at the Cell level.

VOB i shown in FIG. 10 is composed of a composite video stream obtained by synthesizing two video data to the left and right, and a composite audio stream obtained by recording two audio data in channel 1 and channel 2.

Cell B in FIG. 10 is a cell for designating reproduction of the left video data and the audio data recorded on channel 1 in VOB i.
11C is a cell for designating the reproduction of the right video data and the audio data recorded on channel 2 in VOB i.

As described above, the VOB indicates the presence / absence of a combined stream, and the cell specifies video data and audio data to be played back, so that information necessary for playing back the combined stream can be managed.

Next, the details of the management information of the composite stream will be described with reference to FIG. The presence / absence of the composite stream is determined by the stream attribute information VOB_ in the VOB information.
Application identification information Ap in Attribute
This is described in the combined stream identification flag Multi Contens in the application_Inf. If the value of this flag is Yes, it indicates that the VOB is a composite stream, and if No, it indicates that the VOB is not a composite stream. Therefore, in the embodiment of FIGS. 9 and 10, the following values are provided.

Multi Contents = Yes Also, stream attribute information VOB_Attribute
In the video stream attribute information Video_Attri
In the “bute”, the video compression method (MPEG1 or M1)
PEG2) Video Compression
n, TV System indicating the display (NTSC or PAL), aspect ratio of video stream (4:
3 or 16: 9) and the resolution of the video stream (in the case of NTSC, 720x
480, 704x480, 352x480 or 352
x240, PAL, 720x576, 704x5
76, 352x576 or 352x288)
The video resolution is recorded, and has the following values in the embodiment of FIGS. 9 and 10, for example.

Video Compression = MPEG2 TV System = NTSC Aspect Ratio = 16: 9 Video Resolution = 704x480 Video Resolution above Video Resolution
It can be seen that the resolution of each video stream synthesized is less than half the value.

Video Resolution = 352 × 480 Also, audio attribute information Audio_Attribu
te indicates the audio compression method (AC3 / MPEG /
Audio Coding Mode indicating LPCM),
Quantization indicating the quantization size, Sampling Frequency indicating the sampling period
y, Number of audio channels
Channels are recorded, and have the following values in the examples of FIGS.

Audio Coding Mode = AC3 Quantization = 16 bits Sampling Frequency = 48 kHz Number of Channels = dual mono The video information and audio data to be reproduced in the composite information Cell are the Cell attributes and the Cell information is the Cell attribute.
ValidConte in ell_Attribute
nt, and in the embodiment of FIG.
In B, Valid Content = left, and in Cell C, Valid Content = right.

(Switching of Stream Combining) Next, a case where a combined stream and a non-combined stream are switched will be described with reference to FIG.

For example, when recording a drama from 7:00 to 9:00 and news from 8:00 to 10:00 at the same time, the recording of the drama starts at 7:00, but the recording is started at 8:00.
At the same time, it switches to simultaneous recording of drama and news, that is, recording of a combined stream. Since the drama ends at 9:00, the recording is switched from 9:00 to news-only recording.

First, the recording of the drama starts at 7:00. AV data to be recorded is recorded as VOBi,
The VOB_Attribute of OB i is as follows.

[0095] Video_Attribute: Video Compression = MPEG2 TV System = NTSC Aspect Ratio = 4: 3 Video Resolution = 352x480 Audio_Attribute: Audio Coding Mode = AC3 Quantization = 16bit Sampling Frequency = 48kHz Number of Channels = mono Application_Flag: Mulit Contents = No addition, PGC A is generated as a drama playback sequence, and Cell a Val indicating the entirety of VOB i
Since the id Content is not a composite stream, Valid Content = whole.

Next, simultaneous recording of news starts at 8:00. At the start of simultaneous recording, the stream to be recorded becomes a composite stream and the VOB attribute changes. At this point, the VOB is switched. The AV data to be newly recorded include a composite video stream in which a drama is arranged on the left side of the video data, news is arranged on the right side of the video data, and a composite stream VOB j in which the drama is assigned to audio ch1 and the news is assigned to audio ch2. VOB_Attribute of VOB j
e is as follows.

[0097] Video_Attribute: Video Compression = MPEG2 TV System = NTSC Aspect Ratio = 4: 3 Video Resolution = 704x480 Audio_Attribute: Audio Coding Mode = AC3 Quantization = 16bit Sampling Frequency = 48kHz Number of Channels = dual mono Application_Flag: Multi Contents = Yes Also VOB in drama playback sequence PGC A
Cell b indicating the entire section of B is generated, and Cell
Valid Content of b is as follows: Valid Content = left.

PGC B is generated as a news reproduction sequence, and CGC indicating the entire section of VOB j is generated.
Since the valid content of the cell f is a composite stream, the valid content is as follows: Valid Content = right.

Next, since the recording of the drama ends at 9:00, the composite stream returns to the stream to be recorded alone again. At this time, since the attribute of the VOB changes,
Switch B. The AV data to be recorded is recorded as VOB k, and the VOB_Attribute of VOB k is recorded.
Is as follows.

[0100] Video_Attribute: Video Compression = MPEG2 TV System = NTSC Aspect Ratio = 4: 3 Video Resolution = 352x480 Audio_Attribute: Audio Coding Mode = AC3 Quantization = 16bit Sampling Frequency = 48kHz Number of Channels = mono Application_Flag: Multi Contents = No addition, VOB in news playback sequence PGC B
Cell g indicating the entire section of C is generated, and Cell g is generated.
The Valid Content of lg is as follows: Valid Content = whole.

As described above, when simultaneous recording and single recording are switched during recording, the VOB
And the cell are divided and the combined stream is recorded.

(Erasing of VOB) Next, the timing of erasing the data of the combined stream will be described.

Normally, deletion of AV data, that is, VOB, is performed when Cell, which is a unit that defines the entire or partial playback section of the VOB, is deleted in the PGC indicating the playback sequence. However, in the case where a plurality of cells refer to one VOB at the same time as in the present embodiment, for example, in the example of FIG. 12, if the VOB j is deleted at the same time as the deletion of Cell b, the Cell f refers. VOB is lost, and normal reproduction cannot be performed.

Therefore, when deleting AV data, V
Application in OB_Attribute
The _flag is checked, and if the VOB is a composite stream, it is checked whether there is any other Cell that refers to the VOB, and the VOB can be deleted only when there is no Cell that references the VOB.

Note that, without checking the Application_flag, the reference relationship of the Cell to the VOB may be sequentially checked, and then the deletion of the VOB may be determined.

(Configuration of DVD Recorder) FIG.
It is a block diagram of a recorder.

In the figure, reference numeral 1301 denotes a user interface unit for displaying a display to a user and receiving a request from the user; 1302, a system control unit for managing and controlling the whole; 1303 and 1304, a TV tuner, a camera and a microphone Input unit, 1305 is the first
A synthesizing unit for synthesizing inputs from the input unit 1303 and the second input unit 1304, an encoder unit 1306 including a video encoder, an audio encoder and a system encoder, an output unit 1307 including a monitor and a speaker, and 1308 a synthesized stream An enlargement unit that extracts necessary video and audio data from the video data and enlarges the video data.
A decoder section 1310 comprising an audio decoder and a video decoder; 1310 a track buffer;
Is a drive.

First, the recording operation in the DVD recorder will be described with reference to FIG. The user interface unit 1301 first receives a request from the user. The user interface unit 1301 transmits a request from the user to the system control unit 1302, and the system control unit 1302
Interprets the request from the user and issues a processing request to each module. If the request from the user is to record a TV program, the system control unit 1302
3 or the second input unit 1304 is requested to output a TV program.

If the request from the user is a simultaneous recording of two programs or a recording request of the second program during the recording of one program, the system control unit 1302
305 is requested to synthesize and output the inputs from the first input unit 1303 and the second input unit 1304.

The synthesizing unit 1305 reduces the video data from the first input unit 1303 and the second input unit 1304 into a 352 × 480 image obtained by subtracting half a minute in the horizontal direction, respectively.
The image from the input unit 1303 is placed in the left half, and the second input unit 13
The video data obtained by arranging the image from the image 04 in the right half is output.

The details will be described with reference to FIG. Synthetic unit 1
The first image reduction unit 13051 in the 305 is the first input unit 13
Video data from 03 is halved in the horizontal direction to 35
The image is reduced to a 2 × 480 image and recorded in the left half of the image arrangement unit 13053. Similarly, the second image reduction unit 13052 thins the video data from the second input unit 1304 in half in the horizontal direction to reduce it to a 352 × 480 image, and
Record in the right half of 3053. The image arrangement unit 13053 outputs the recorded 704 × 480 composite video data.

Further, the synthesizing unit 1305 is connected to the first input unit 13
Audio data from channel 03 to audio channel 1
Then, dual monaural audio data obtained by combining the audio data from the second input unit 1304 with the audio channel 2 is output.

If the request from the user is only to record one program, the system control unit 1302 requests the synthesizing unit 1305 to output through, and the synthesizing unit 1305 outputs the input data as it is.

The encoder unit 1306 includes a synthesizing unit 1305
It performs video encoding of video data and audio encoding of audio data sent from, and performs system encoding on the encoded video data and audio data and outputs the encoded data to the track buffer 1310.

[0115] The stream data stored in the track buffer 1310 is transmitted to the DVD-
It is recorded on a RAM disk.

At this time, what is important is the processing when the number of recorded programs is switched from one program to two programs or from two programs to one program. As described above, at the composite stream boundary, the system control unit 1302 and the encoder unit 1306 accurately determine the stream boundary to switch the VOB, which is a management unit of the stream, and to switch the encoding mode (dual monaural stream) at the time of audio encoding. You have to be aware.

Naturally, the system control unit 1302 recognizes the switching of the number of recorded programs. However, since a processing delay occurs in the encoder, it is impossible to know the VOB break accurately. Therefore, the following processing is required.

The synthesizing unit 1305 includes the system control unit 130
When a request for combining input data or canceling the combining (through output) is received from 2, a signal for switching the output data is sent to the encoder unit 1306 when the combining of the input data starts or ends.

When receiving the output data switching signal from the synthesizing unit 1305, the encoder unit 1306 switches the audio encoding mode from monaural to dual monaural or from dual monaural to monaural. In the video encoding process, a GOP boundary is forcibly provided, and a VOB boundary is generated.

Further, when the encoder unit 1306 starts the system encoding of the head data of the new GOP, the encoder unit 1306 notifies the system controller 1302 of the switching of the encoding. At the same time, the VOB data size and the VOB data required to create the VOB management information
The number of frames is passed to the system control unit 1302.

By the above processing, the system control unit 13
02 can know the exact break of the composite stream.

The encoder section 1306 is composed of the synthesizing section 1
Although the switching of the synthesized data is recognized by the output data switching signal from the 305, the switching of the synthesized data is recognized by switching the horizontal resolution of the video signal from the synthesizing unit 1305 (for example, from 352 to 704). Is also possible.

Finally, a program recording end command is issued from the system control unit 1302 to the first input unit 1303 and the second input unit 13.
04 and the synthesizing unit 1305, and each module ends its processing. Similarly, the encoder unit 13
06 also receives a recording end command from the system control unit 1302, and returns to the system control unit 1302 the VOB data size and the number of VOB frames required to stop the encoding process and create VOB management information. After all the stream data recorded in the track buffer 1310 has been recorded on the DVD-RAM through the drive 1311, the system control unit 1302 sends the VOB management information and the C
Cell management information is generated and recorded on the DVD-RAM through the drive 1311, and all recording processing ends.

Next, the reproducing operation in the DVD recorder will be described with reference to FIG. The user interface unit 1301 first receives a request from the user. The user interface unit 1301 transmits a request from the user to the system control unit 1302, and the system control unit 1302
Interprets the request from the user and issues a processing request to each module. If the request from the user is PGC reproduction, the system control unit 1302
PGC information is read through The corresponding VOB information is read from the VOB_ID described in the Cell information in the read PGC information, and the Cell information and the VO
A recorded on the DVD-RAM disk from the B information
V data is read out, and the track buffer 131
Store to 0.

Next, the system control unit 1302 issues a decoding request to the decoder unit 1309. Decoder section 130
9 reads the stream data stored in the track buffer 1310, decodes the stream data,
Outputs decoded data. The decoded AV data passes through the enlargement unit 1308 and is output to the monitor and the speaker by the output unit 1307.

At this time, it is important that when the Multi Contents information in the VOB management information is Yes, the stream being decoded is a composite stream. In this case, the system control unit 1302 checks the Cell_Attribute information in the Cell information, and checks which video data and audio data in the combined stream indicates reproduction of the video data and audio data. Specifically, the Valid in the Cell_Attribute is
If the value of Content is Left, the corresponding Cell
Indicates that the video data is on the left side of the screen and the audio data is on the channel 1 side, and Cell_Attr
If the value of the Valid Content in the
In the case of ght, the video data of the cell is on the right side of the screen, and the audio data is on the channel 2 side.

The system control unit 1302 sets Cell_At
If the value is left according to ValidContent in the tribute information, the decoder 1309 instructs the decoder 1309 to decode the audio of channel 1 and instructs the enlargement unit 1308 to extract the left half of the input video data and output the enlarged output. . Conversely, Cell_At
If the value of Valid Content in the tribe information is right, the system control unit 1302 instructs the decoder unit 1309 to perform audio decoding of channel 2, extracts the right half of the input video data to the enlargement unit 1308, and performs enlargement output. To indicate that

In the present embodiment, the input image is
Although explained with 2x480, 704x480 and 544x4
It may be 80. Further, the input 1 and the input 2 may have different sizes, and it is sufficient that the subsampled result is 360, 352, or 180.

Further, in this embodiment, the size of the composite image is described as 702 × 480.
It may be 0x240.

Further, in the present embodiment, the size of the subsampled image has been described as being left-right (or up-down) coincident.
By using a configuration having each image size information in the VOB management information or the cell management information, the sub-sampled image sizes do not have to be matched.

In this embodiment, the sub-sampling of the input image is performed in the horizontal direction. However, the sub-sampling may be performed in the vertical direction. It does not matter.

Further, in the present embodiment, the input audio data is described as monaural, but it may be stereo or multi-channel audio. In this case, the audio data may be mixed in the synthesizing unit.

In this embodiment, one audio stream (synthesized stream) has been described. However, the cost of an audio encoder is lower than that of a video encoder.

Further, in the description of the recording operation of this embodiment, the video image size of VOB i and VOB k is described as 352, but may be 720 or 704, and the video image size is not limited. In the present embodiment, the reason why the video image size is reduced to 352 in the horizontal direction is that the resolution of each of the drama and news is reduced to 352 in VOB j. In general, the higher the resolution, the better the image quality. For example, when the resolution of a drama is suddenly reduced by half from 704 to 352, the image quality suddenly deteriorates, resulting in discomfort to the viewer.

In the description of the recording operation of this embodiment, the audio of VOB i and VOB k has been described as monaural. However, they may be recorded in stereo respectively, and the number of audio channels is not limited. . In the present embodiment, the reason why the monaural audio is used is that the sound of each of the drama and the news in VOB j is adjusted to be monaural. In general, the greater the number of audio channels, the better the sound quality, and this is particularly noticeable in monaural and stereo.For example, when the sound of a drama suddenly changes from stereo to monaural, the sound quality suddenly deteriorates, and the viewer cannot hear the sound. The result is a pleasant feeling.

Also, in this embodiment, the presence or absence of a combined stream is managed at the VOB level, and
Although the management at the cell level is performed, for example, the behavior at the time of reproduction may be managed at the VOB level. In this case, a configuration is provided in which a plurality of (two) VOB management information exists for one VOB. Similarly, all information may be managed at the Cell level.

In this embodiment, the presence or absence of a combined stream is determined by the VOB management information in the VOB table.
Multi Content in _Attribute
s, but is not necessarily limited to this. For example, M
anufactor_Inf. And the field may be read out by the player.

Further, in the present embodiment, the behavior at the time of reproduction with respect to the composite stream is described by the PG in the PGC table.
Cell_Attri in Cell information in C management information
The record was recorded in the Valid Content in the bute, but is not necessarily limited to this. For example, Manufac
cure_Inf. And the field may be read out by the player.

In the present embodiment, the number of AV data to be combined is two.
Audio data is divided into two mono 2
It is also possible to combine four pieces of AV data as a stream, and the number of pieces of AV data to be combined is not essentially limited.

[0140]

According to the present invention, there is provided an optical disc on which at least one AV stream composed of at least two pieces of video data is recorded, wherein the AV stream is formed on a spatial coordinate axis. Video data is compositely recorded. Particularly, the two or more pieces of video data are divided and recorded in a horizontal direction or a vertical direction on a spatial coordinate axis of the AV stream. As a result, an effect is obtained that two or more video data can be recorded as one video data on an optical disc.

Further, at least two or more audio data which are reproduced in synchronization with each of the two or more video data are recorded in the AV stream. As a result,
An effect is obtained that audio data to be reproduced in synchronization with two or more pieces of video data can be recorded on an optical disc.

[0142] Further, management information on the AV stream is recorded on the optical disc, and the AV stream management information includes identification information indicating that the AV stream is composed of at least two or more pieces of video data. Has been recorded.

As a result, it is possible to determine whether the AV stream recorded on the optical disc is a composite stream composed of two or more pieces of video data.

[0144] Further, the reproduction sequence information of the AV stream is recorded on the optical disc, and identification information for extracting one piece of video data and audio data from the AV stream is recorded in the reproduction sequence information. .

As a result, the required video data and audio data in the combined AV stream can be determined from the reproduction sequence information logically constituting the program, and the user does not need to be aware of the existence of the combined AV stream. Thus, the effect that the program can be reproduced only by specifying the program to be reproduced is obtained.

An optical disk recording apparatus for recording the optical disk, comprising at least two or more input units for inputting video data and audio data, wherein at least two or more video data and A synthesizing unit for synthesizing audio data into one video data and audio data, an encoder unit for encoding the video data and audio data into an AV stream, a system control unit for generating management information of the AV stream, It comprises an AV stream and a drive for recording the AV stream management information on an optical disc.

In particular, the synthesizing unit includes: an image reducing unit that reduces video data input from the at least two or more input units in a horizontal direction or a vertical direction on a spatial coordinate axis;
It comprises an image recording / synthesizing unit for temporarily recording at least two or more pieces of video data reduced on the spatial coordinate axes, and outputting the data as synthesized video data. As a result, an effect is obtained in which two or more pieces of video data and audio data can be recorded on an optical disc as a combined AV stream in which one piece of video data and one piece of audio data are combined.

An optical disk recording method for recording the optical disk, comprising: a first input step and a second input step for inputting video data and audio data; A combining step of combining the video data and the audio data into an AV stream;
The system comprises a system control step of generating management information of the AV stream, and a recording step of recording the AV stream and the AV stream management information on an optical disc.

In particular, the synthesizing step includes an image reducing step of reducing video data input from the first input step and the second input step in a horizontal direction on a spatial coordinate axis, and a reducing step on the spatial coordinate axis. The image recording / combining step of temporarily recording at least two or more pieces of image data thus obtained and outputting the resultant as combined video data.

As a result, an effect is obtained that two or more pieces of video data and audio data can be recorded on an optical disc as a combined AV stream obtained by combining the two pieces of video data and audio data.

An optical disk reproducing apparatus for reproducing the optical disk, comprising: a drive for reading an AV stream and AV stream management information from the optical disk; and a drive for determining whether the AV stream is a composite stream based on the AV stream management information. A system control unit for determining, a decoding unit for decoding only one audio channel and decoding of video data according to an instruction of the system control unit when the AV stream is a combined AV stream, In the case of an AV stream, it is composed of an enlargement unit for extracting and enlarging a designated area on the spatial coordinate axis of the video data according to an instruction of the system control unit, and an output unit for displaying and outputting the video data and audio data. .

As a result, an effect is obtained that it is possible to combine two or more pieces of video data and audio data into one piece of video data and audio data to reproduce a combined AV stream recorded on an optical disk.

An optical disc reproducing method for reproducing the optical disc, comprising: a reading step of reading an AV stream and AV stream management information from the optical disc; and determining whether the AV stream is a composite stream based on the AV stream management information. A decoding step of decoding only one audio channel and decoding video data in accordance with an instruction of the system control unit when the AV stream is a composite AV stream;
In the case where the V stream is a composite AV stream, from an enlarging step of extracting and enlarging a designated area on the spatial coordinate axis of the video data and an output step of displaying and outputting the video data and audio data in accordance with an instruction of the system control step It is configured.

As a result, an effect is obtained that it is possible to combine two or more pieces of video data and audio data into one piece of video data and audio data to reproduce a combined AV stream recorded on an optical disk.

[Brief description of the drawings]

FIG. 1 is a block diagram of a drive device of a DVD recorder.

FIG. 2 is a diagram showing an address space on a disk and a data accumulation amount in a track buffer;

FIG. 3 is a picture correlation diagram in an MPEG video stream.

FIG. 4 is a configuration diagram of an MPEG system stream.

FIG. 5 is a configuration diagram of an MPEG system decoder (P-STD).

FIG. 6 is a diagram showing an example of an MPEG multi-stream.

FIG. 7 is a diagram showing a directory structure and a physical arrangement on a disk.

FIG. 8 is a diagram showing management information data and stream data.

FIG. 9 is a diagram showing generation and reproduction of a composite stream.

FIG. 10 is a diagram showing a method of managing a composite stream.

FIG. 11 is a diagram showing management information of a combined stream.

FIG. 12 is a diagram showing switching of simultaneous recording of two programs.

FIG. 13 is a configuration diagram of a DVD recorder.

FIG. 14 is a diagram showing details of a synthesizing unit of the DVD recorder;

[Explanation of symbols]

 Reference Signs List 11 optical pickup 12 ECC processing unit 13 track buffer 14 switch 15 encoder unit 16 decoder unit 41 pack header 42 packet header 43 payload 51 STC 52 demultiplexer 53 video buffer 54 video decoder 55 reorder buffer 56 switch 57 audio buffer 58 audio decoder 1301 user Interface section 1302 System control section 1303 First input section 1304 Second input section 1305 Synthesis section 1306 Encoder section 1307 Output section 1308 Enlargement section 1309 Decoder section 1310 Track buffer 1311 Drive 13051 First image reduction section 13052 Second image reduction section 13053 Image Arrangement section

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuhiko Nakamura 1006 Kazuma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (14)

[Claims] 1. An optical disc on which at least one AV stream composed of at least two video data is recorded, wherein the AV stream is composed of the two or more video data on a spatial coordinate axis. An optical disc characterized by being recorded. 2. The optical disc according to claim 1, wherein the two or more pieces of video data are divided and recorded in a horizontal direction on a space coordinate axis of the AV stream. 3. The optical disc according to claim 1, wherein the two or more pieces of video data are divided and recorded in a vertical direction on a space coordinate axis of the AV stream. 4. The optical disk according to claim 1, wherein at least two or more pieces of audio data reproduced in synchronization with the two or more pieces of video data are included in the AV stream. An optical disc characterized by being recorded on a disc. 5. The optical disk according to claim 1, wherein management information on the AV stream is recorded.
The management information includes at least two AV streams.
An optical disc characterized by recording identification information indicating that it is composed of one or more pieces of video data. 6. The optical disc according to claim 1, wherein reproduction sequence information of the AV stream is recorded, wherein the reproduction sequence information includes identification information for extracting one piece of video data and audio data from the AV stream. An optical disc on which information is recorded. 7. An optical disk recording apparatus for recording the optical disk according to claim 1, wherein:
A combining unit having at least two or more input units for inputting video data and audio data, and combining at least two or more video data and audio data input from the input unit into one video data and audio data; An encoder unit for encoding the video data and audio data into an AV stream, a system control unit for generating management information for the AV stream, and a drive for recording the AV stream and the AV stream management information on an optical disc. An optical disc recording device characterized by the following: 8. The optical disk recording apparatus according to claim 7, wherein the synthesizing unit is configured to reduce video data input from the at least two or more input units in a horizontal direction on a spatial coordinate axis; Temporarily recording at least two or more video data reduced on the spatial coordinate axes,
An optical disc recording apparatus comprising an image recording / synthesizing unit for outputting as synthesized video data. 9. The optical disk recording apparatus according to claim 7, wherein the synthesizing unit is configured to reduce video data input from the at least two or more input units in a vertical direction on a spatial coordinate axis; Temporarily recording at least two or more video data reduced on the spatial coordinate axes,
An optical disc recording apparatus comprising an image recording / synthesizing unit for outputting as synthesized video data. 10. An optical disk recording method for recording an optical disk according to claim 1, wherein a first input step and a second input step of inputting video data and audio data, A synthesizing step of synthesizing the video data and audio data into one video data and audio data, an encoding step of encoding the video data and audio data into an AV stream, and a system control step of generating management information of the AV stream. , The AV
Recording a stream and the AV stream management information on an optical disk. 11. The optical disc recording method according to claim 10, wherein said synthesizing step reduces video data input from said first input step and said second input step in a horizontal direction on a spatial coordinate axis. An optical disk recording method, comprising: an image reduction step of performing recording; and an image recording / combining step of temporarily recording at least two or more pieces of image data reduced on the spatial coordinate axis, and outputting the resultant data as combined video data. 12. The optical disc recording method according to claim 10, wherein the synthesizing step reduces video data input from the first input step and the second input step in a vertical direction on a spatial coordinate axis. An optical disk recording method, comprising: an image reduction step of performing recording; and an image recording / combining step of temporarily recording at least two or more pieces of image data reduced on the spatial coordinate axis, and outputting the resultant data as combined video data. 13. An optical disc reproducing apparatus for reproducing the optical disc according to claim 1, wherein the drive reads an AV stream and AV stream management information from the optical disc, and reads the AV stream management information from the AV stream management information. A system control unit for determining whether or not the AV stream is a composite stream; and, if the AV stream is a composite AV stream, decoding of only one audio channel and decoding of video data in accordance with instructions from the system control unit. A decoder unit for performing the decoding, and when the AV stream is a synthetic AV stream, an expansion unit for extracting and enlarging a designated area on the spatial coordinate axis of the video data in accordance with an instruction of the system control unit, and the video data and the audio data. Output from the output unit An optical disk reproducing apparatus characterized by being formed. 14. An optical disk playback method for playing back an optical disk according to claim 1, wherein: a reading step of reading an AV stream and AV stream management information from the optical disk; A system control step of determining whether the AV stream is a composite stream from
A decoding step of decoding only one audio channel and decoding video data according to an instruction of the system control unit when the AV stream is a synthetic AV stream; and An optical disc reproducing method, comprising: an enlarging step of extracting and enlarging a designated area on a spatial coordinate axis of the video data according to an instruction of the system control step; and an output step of displaying and outputting the video data and audio data.