JPH0974535A - Video data recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To record video data encoded in variable length by adding dummy data to the encoded data to record them on a recording medium in fixed data length and therefore facilitating the control of data quantity in a reproduction mode via a simple recording circuit and a control circuit. SOLUTION: Plural video data which are reproduced from three tapes where the programs A to C are recorded at a VTR part 11 are encoded in variable length at an MPEG2 moving picture experts group encoder part 12. The video data encoded for every GOP(group of pictures) are primarily stored in the 1st to 3rd FIFO 13-1 to 13-3 and then read out to the 1st to 3rd dummy data insertion parts 14-1 to 14-3 . Thus the dummy data are added to those encoded video data, so that the data quantity of 250Kbytes can be obtains for every GOP. Then the video data are selected by a multiplexer 15 in the order of programs A to C and is every 250Kbytes and then successively recorded on a recording medium 17 via an SCSI interface 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video for recording video data for use in a system for simultaneously sending a plurality of types of video data to a plurality of channels such as near video on demand (NVOD). The present invention relates to a data recording device and a video data reproducing device for reproducing the video data recorded by the video data recording device.

[0002]

2. Description of the Related Art A program is sent to a plurality of channels at predetermined time intervals, a channel of the program starting from the next time zone is selected in response to a request generated in a certain time zone, and the program is supplied.・ Video on demand (NVOD)
The system is being put to practical use. As a method of providing video data to such an NVOD system, the video data is compressed and recorded on a randomly accessible recording medium by the progress of the video data compression technology and recording technology in recent years, and the recording medium Is being used at a high speed to simultaneously reproduce a plurality of types of video data. However, even in that case, in order to access multiple types of video data at high speed, the video data that must be continuously reproduced and output simultaneously is recorded at predetermined positions on the recording medium in predetermined units. In addition, a method of continuously accessing this is adopted.

By the way, such video data is converted into, for example, MPEG2 (Moving Picture coding Experts Group).
In the case of performing variable length coding by a method such as a moving picture coding method according to
There are a method of recording on the recording medium in units of video data for each predetermined time, and a method of recording on the recording medium in units of video data for each predetermined data length. The recording state of the video data of each method is shown in FIGS. FIG.
FIG. 11 is a diagram showing a state in which image data is recorded on a recording medium in units of image data for each predetermined time, and FIG. 10 is a diagram showing a state in which image data is recorded in a recording medium in units of image data for each predetermined data length. Is.

In FIGS. 9 and 10, A,
B and C respectively indicate the type of program, A0 to A5, B0 to B
Data 5 and C0 to C5 represent encoded video data for each predetermined time of each program. When the video data is recorded sequentially in units of video data for each predetermined time, as shown in FIG. 9, A0, B0, C0, A
Data is recorded on the recording medium in the order of 1, ... When video data is recorded in units of video data of a predetermined data length, each video data is divided into units (250 sectors in FIG. 10), and A,
It is repeatedly recorded in the order of B and C.

[0005]

However, in any of the above-described method of encoding and recording the video data for a predetermined time as a unit and recording by the predetermined data length of the encoded video data as a unit. However, there is a problem in that the device configuration and control method for recording and reproduction become complicated.

For example, when data is recorded by encoding video data for a predetermined time as a unit, as shown in FIG. 9, the data length of each video data for each unit fluctuates, and recording and reproduction are performed. There was a problem that the control of was complicated. In addition, when recording and reproducing data in a block having a predetermined data length according to the characteristics of the recording medium, there is a problem that the block length is difficult because the video data has different data lengths. Further, in the method of recording the encoded video data for each predetermined data length, since the reproduction time of the video data for each data varies, it is necessary to strictly manage the data length, and the control becomes complicated. There was a problem of becoming. Further, in order to properly reproduce the plurality of types of video data, a large capacity buffer memory is required on the reproducing side, which causes a problem that the device scale becomes large.

Therefore, an object of the present invention is to record variable length coded video data on a recording medium so that the data amount can be easily controlled at the time of reproduction by a simple recording circuit and its control circuit. To provide a recording device. Another object of the present invention is to provide a video data reproducing apparatus for reproducing variable length coded video data from a recording medium so that the data amount can be easily controlled by a simple reproducing circuit and its control circuit. To provide.

[0008]

In order to solve the above-mentioned problems, by encoding video data for a predetermined time as a unit and adding dummy data to the encoded data, the data length is fixed. Then, the data is recorded on the recording medium.

Therefore, in the video data recording apparatus of the present invention, the variable length coding means performs variable length coding on each of a plurality of types of video data, and the variable length coded video data is recorded at predetermined time intervals. On the other hand, the complementary data adding means loads the complementary data so that each data has a predetermined data length. It is preferable to use meaningless dummy data as the video data as the complementary data, but any data may be added as long as it is distinguishable from the video data. And
The data recording means records the fixed-length video data on a recording medium so that the data sent simultaneously can be continuously accessed. The plural types of video data include video data of separate programs and video data of the same program in different time zones.

Further, in the video data reproducing apparatus of the present invention, each of a plurality of types of video data output simultaneously by the data reproducing means from the recording medium in which the video data is recorded by the video data recording apparatus of the present invention. The data of the predetermined length are simultaneously read out, and the data output means separates the complementary data from the read-out data, and outputs the separated data for each type of the video data.

Specifically, the data output means has a complementary data separating means and a data distributing means, and the complementary data separating means separates the complementary data from the read data, and the data distributing means. In, the respective data are distributed for each type of the video data.

[0012] More specifically, the data output means is
A data distribution means and a video data extraction means, wherein the data distribution means distributes each of the read data for each type of video data, and the video data extraction means distributes each of the distributed video data. The video data is extracted by decoding the variable-length coded data of 1.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a video data recording apparatus and a video data reproducing apparatus of the present invention will be described with reference to the drawings. First, an embodiment of a video data recording apparatus of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing the configuration of the video data recording apparatus of this embodiment. The video data recording device 10 includes a VTR unit 11, M
PEG2 encoder unit 12, FIFO unit 13, dummy data insertion unit 14, multiplexer 15, SCSI interface 16, recording medium 17, and controller 18
Having. The video data recording device 1 according to the present embodiment
Reference numeral 0 is a device that creates data for application to an NVOD system that simultaneously sends video data to n channels and records the data on a recording medium.

First, the configuration of each section will be described. VT
The R section 11 is a video tape recorder for supplying source video data, which is composed of _n VTRs 11 _{-1 to} 11 _-n . The n pieces of source video data transmitted in the NVOD system are provided in the state of being recorded on the VTR tape, reproduced in the VTRs 11 _{-1 to} 11 _-n , and output to the MPEG2 encoder unit 12. In the present embodiment, the video signal output from the VTR unit 11 is 30 frames per second and the raster 5
These are 25 video signals.

The MPEG2 encoder unit 12 has n M
PEG2 encoders 12 _{-1 to} 12 _-n , VT
The n video data input from the n VTRs 11 _{-1 to} 11 _{-n of the} R unit 11 are each encoded by MPEG-2 and output to the FIFO unit 13. In the present embodiment, the MPEG2 encoder unit 12 encodes 15 frames as 1 GOP (Group Of Picture), and
Encoding is performed so that the maximum code amount is within 4 Mbps.

The FIFO unit 13 includes n FIFOs 13 _-1.
To 13 is constructed from _-n, n pieces of encoded video data input from the n-number of MPEG2 encoder 12 _-1 to 12 _-n of MPEG2 encoder 12, the buffer temporarily stores memory Is. The encoded video data recorded in the FIFO unit 13 is appropriately read by the dummy data insertion unit 14.

The dummy data insertion unit 14 is a first dummy
Data insertion unit 14_-1~ Nth dummy data insertion unit 14_-n
Of n dummy data insertion parts,
FO13_-1~ 13_-nThe video data read from each
Dummy data is added so that the predetermined data amount is obtained.
In the present embodiment, 1 GOP encoded video
The data amount becomes 2Mbit (= 250Kbyte).
So that the FIFO13 _-1~ 13_-nEach video read from
Add dummy data to the data. In addition, this embodiment
In, the predetermined value set in advance is used as dummy data.
It shall be recorded. Video data with dummy data added
The data is output to the multiplexer 15.

The multiplexer 15 multiplexes the video data input from the n dummy data insertion units 14 _{-1 to} 14 _-n and outputs it to the SCSI interface 16.
In the present embodiment, the multiplexer 15 sequentially selects n pieces of video data input from the dummy data insertion unit 14, time division multiplexes them, and outputs them to the SCSI interface 16.

The SCSI interface 16 controls the recording medium 17 to actually record the video data input from the multiplexer 15 on the recording medium 17. Recording medium 1
Reference numeral 7 denotes a medium on which video data is actually recorded, which is a hard magnetic disk device in the present embodiment.
In this hard magnetic disk device, one sector is 1 Kbyte. In this embodiment, the multiplexer 15 is connected to the SCSI interface 16 by 1G.
Since 250 Kbytes of video data for each OP are sequentially input, the SCSI interface 16 sequentially records this data in the recording area of each 250 sectors of the recording medium 17.

The controller 18 controls the operation of each part constituting the video data recording device 10, and also the timing of data transfer of each of the above-mentioned constituent parts connected in a pipeline manner and the n parallel constituent parts. The operation timing and the like are controlled so that the video data recording device 10 performs a desired operation.

Next, the operation of the video data recording device 10 will be described. For the sake of simplicity of explanation, each 3
A case where three pieces of video data per second are encoded, multiplexed, and recorded will be described. First, the three VTR tapes on which such three programs A, B and C are recorded are
The third VTRs 11 _{-1 to} 11 _-3 are set and reproduced. Then, the reproduced video data are input to the first to third MPEG2 encoders 12 _{-1 to} 12 _-3 , and MP
It is encoded by EG2. As described above, this encoding is performed so that the maximum encoding amount is 4 Mbps or less with 15 frames, that is, 0.5 seconds of video data as 1 GOP.

FIG. 2 shows the encoded data amount of each of the programs and GOPs of the encoded result. 2A and 2B are diagrams showing the encoded data amount for each program, FIG. 2A is a diagram showing the data amount for each GOP, and FIG. 2B is a diagram showing the total encoded amount of each program. In FIG. 2, A0 to A5 are 6 GOPs for every 0.5 seconds of the program A, and B0 to B5 are O. 6 GOPs every 5 seconds, and C0 to C5 show 6 GOPs every 0.5 seconds of program C.

The encoded video data for each GOP is temporarily stored in the first to third FIFOs 13 _{-1 to} 13 _-3 . Next, first to third FIFO 13 _-1 to 13
_-3 , the respective video data stored in _-3 are read out to the first to third dummy data insertion units 14 _{-1 to} 14 _-3 , respectively, and the respective GOPs are read.
Dummy data is added so that the video data for each becomes a data amount of 250 Kbytes. And this 250K
The video data for each byte is selected by the multiplexer 15 in the order of program A, program B, and program C, and is sequentially recorded on the recording medium 17 via the SCSI interface 16.

The recorded state is shown in FIG. FIG.
FIG. 6 is a diagram showing a state in which video data having a fixed length of 250 Kbytes is recorded on a recording medium. In addition, the shaded portion in FIG. 3 indicates the dummy data.

As described above, in the video data recording apparatus 10 of the present embodiment, even if the video data is variable length coded by a method such as MPEG2, it can be treated as fixed length data at the time of recording. Therefore, various data processes can be easily controlled, and the device can be simplified. In addition, the video data recording device 10 of the present embodiment
In the above, data can be recorded by making the data length of each GOP smaller, and by doing so, the capacity of the buffer memory for each channel can be reduced in the NVOD system and the like.

In the present embodiment, each GOP is
Dummy data is added to each data, which may give the impression that the recording area of the recording medium is wasted. However, the difference in the coded data amount for each GOP in the MPEG2 coding is small compared to the coded amount. Furthermore, if necessary, the encoding unit can be controlled to reduce the difference in encoded data amount. That is, it is possible to perform appropriate encoding in consideration of the amount of dummy data according to the type of video, the required image quality, etc., and the area occupied by dummy data does not pose a big problem.

Next, an embodiment of the video data reproducing apparatus of the present invention will be described with reference to FIGS. 4 and 5. FIG.
FIG. 3 is a block diagram showing a configuration of a video data reproducing device of the present embodiment. The video data reproducing device 20 includes a recording medium 21, a SCSI interface 22, and a data distribution unit 2.
3 and n data output units 24 _{-1 to} 24 _-n and a controller 28. The video data reproducing device 20 of the present embodiment is a device which reproduces the video data recorded on the recording medium in the above-mentioned video data recording device 10 and simultaneously outputs the video data to n channels.

First, the configuration of each part will be described. The recording medium 21 is a recording medium on which video data is recorded in the format shown in FIG. 3, for example, by the above-described video data recording device 10, and is a hard magnetic disk device in the present embodiment. SCSI interface 2
2 controls the recording medium 21 based on the control signal from the controller 28, reads the video data recorded on the recording medium 21, and outputs it to the data distribution unit 23. Since n pieces of video data are continuously recorded in the recording medium 21 in units of data for a predetermined time, SCSI
The interface 22 reads out these data at least within the predetermined time.

The data distribution unit 23 distributes the video data input from the SCSI interface 22 for each video data and outputs it to the data output unit 24. As described above, since n pieces of video data are simultaneously read and output from the SCSI interface 22 for each predetermined time, n pieces of data are output for each type of video data using the data as a unit. The data is appropriately output to any one of the units 24 _{-1 to} 24 _-n .

The data output unit 24 is a processing unit for outputting the video data sequentially input from the data distribution unit 23 as a normal video signal, and outputs n data corresponding to each of the n channels. It has sections 24 _{-1 to} 24 _-n , which output n pieces of video data in parallel. Each data output unit 24 _-i (i = 1 to n) has a FIFO 25 _-i , MPE.
G2 decoder 26- _i and video interface 27
_{with -i} .

[0031] FIFO25 _-i (i = 1~n) is a buffer memory for temporarily storing image data input from the data distribution unit 23, FIFO 25 contents of _-i are MPEG2 decoder 26 _{- It} is read from _{i as} appropriate.
The amount of data buffered in the FIFO 25 _-i is managed by output to the controller 28.

MPEG2 decoder 26 _-i (i = 1 to n)
Sequentially reads and decodes the encoded video data buffered in the FIFO 25 _-i , generates uncompressed video data, and outputs the uncompressed video data to the video I / F 27 _-i .
The video data buffered in the FIFO 25- _i is data in which dummy data is added to the video data for a predetermined time which is variable length coded by MPEG2, but the dummy data irrelevant to the video data is MPE.
When it is decoded by the G2 decoder 26 _-i , it is ignored and excluded as meaningless data. Therefore, MP
The EG2 decoder 26 _-i outputs only the original video data that is not affected by the dummy data. The video I / F 27 _-i converts the video data decoded by the MPEG2 decoder 26 _-i into a video signal and outputs it to each channel.

The controller 28 controls the operations of the respective parts constituting the video data reproducing device 20, and the timing of data transfer between the respective parts and the data output parts 24 _{-1 to} 24 _-n provided in parallel. Controls the operation timing. The controller 28 controls the video data reproducing device 20 so that the video data reproducing device 20 performs a desired operation based on a control signal input from a higher-order overall control unit.

Next, the operation of the video data reproducing apparatus 20 will be described. In the present embodiment, a recording medium in which three video data of programs A, B, and C are recorded as shown in FIG. 3 is used, and the three programs are simultaneously concurrently processed in three channels. The operation of the video data reproducing device 20 will now be described with reference to an example of outputting the video data.

First, as shown in FIG. 3, a recording medium 21 on which video data is recorded is a SCSI interface 22.
The data is read out at a speed of at least 1500 sectors per second or more. The read video data is distributed to each channel in the data distribution unit 23 for each video data. For example, first, the video data A0 of the program A is input to the channel 1, that is, the FIFO 25 _-1 of the data output unit 24 _-1 ,
Video data B0 is channel 2 of the program B, that are input to FIFO 25 _-2 of the data output unit 24 _-2, video data C0 channel 3 program C, that the input to the FIFO 25 _-3 of the data output unit 24 _-3 To be done.

Next, the video data buffered in each of the FIFOs 25 _{-1 to} 25 _-3 is sequentially read by the MPEG2 decoders 26 _{-1 to} 26 _-3 and decoded, and the dummy data is excluded to remove the non-existence. The compressed video data is output to the video I / Fs 27 _{-1 to} 27 _-3 . Video I / F
In 27 _{-1 to} 27 _-3 , the video data is further converted into a desired video signal and output from each channel.

By performing such processing on the subsequent data of each program in sequence, as shown in FIG.
One program can be output to three channels simultaneously. FIG. 5 shows a video data reproducing device 20 according to the present embodiment.
It is a figure which shows the example of the reproduction output of.

As described above, in the video data reproducing apparatus 20 according to the present embodiment, since it is sufficient to sequentially read the fixed length data from the recording medium, high speed access becomes possible,
The control circuit for data access is also simplified. Also,
Since the recorded video data is coded by variable-length coding, coding suitable for the characteristics of the video is performed, and high-quality video can be reproduced. Further, since data for a predetermined time is recorded in one video data, the buffer memory on the reproducing unit side can be easily managed, and the capacity of the buffer memory can be reduced. Note that the dummy data added for access with a fixed length while performing variable-length coding can be excluded without performing any special processing at the image decoding stage. There is no adverse effect on.

The present invention is not limited to this embodiment, and various modifications can be made. For example, each unit of the video data recording apparatus 10 shown in FIG. 1 is provided with n constituent units in parallel corresponding to the number of video data to be reproduced simultaneously. However, in the video data recording device, it is not necessary to simultaneously record the respective video data in the recording medium 17. The configuration may be such that one image data is processed in order. In that case, the video data recording device 10 may have a configuration as shown in FIG.

FIG. 6 is a diagram showing the configuration of a video data recording device 10b which is a modification of the video data recording device 10. In the video data recording device 10b shown in FIG.
VTR unit 11, MPEG2 encoder unit 12, FIFO
The unit 13 and the dummy data insertion unit 14 each include one VTR 11 _-1 , MPEG2 encoder 12 _-1 , FIF.
It only has O13 ₋₁ and the dummy data insertion unit 14 ₋₁ . Moreover, the multiplexer 15 is not provided.

The video data recording apparatus 10 having such a configuration
In b, a plurality of types of video data to be recorded are reproduced in order, each is encoded, dummy data is added, and the data is recorded in a predetermined area of the recording medium 17, so that the recording medium is recorded in the same manner as the video data recording device 10. A plurality of types of video data can be recorded in 17. In such a video data recording device 10b, the processing time is n times that of the video data recording device 10 in FIG. 1, but the scale of the device is 1 / n.
Degree. The video data recording device of the present invention may have such a configuration.

Further, in the above-mentioned video data reproducing apparatus 20, when decoding the video data by the MPEG2 decoder 26, dummy data is excluded by ignoring meaningless data. However, the dummy data may be separated immediately when the video data is read from the recording medium 21. A video data reproducing device having such a configuration is shown in FIG. In the video data reproducing device 20b shown in FIG. 7, a dummy data separating section 29 is provided at the subsequent stage of the SCSII / F22, and the video data read from the recording medium 21 is converted into dummy data by the dummy data separating section 29. After being excluded, it is input to the data distribution unit 23. According to the video data reproducing device 20b having such a configuration, it is not necessary to pay attention to whether the decoding unit in the data output unit 24 has a function of excluding dummy data. Further, it is also effective when outputting video data to a channel in a coded state without decoding.

Further, in the present embodiment, an example has been described in which the recording medium on which the three program data are recorded is reproduced and the three programs are simultaneously output to the three channels. Such an operating method can be applied to the NVOD system that sends program data in response to a request, but other operating methods are also possible. For example, one program data is shifted to n channels little by little and outputted simultaneously, and the channel from which the program starts from the beginning is automatically selected at the time closest to the time when the request is made. In this case, it is possible to construct an NVOD system capable of transmitting a program in response to a request generated at an arbitrary time.

FIG. 8 shows a state in which the above-mentioned video data reproducing apparatus 20 reproduces such video data. According to FIG. 8, three types of video data A, B and C are simultaneously output to three channels, and further three types of video data A, B and C are sequentially output to each channel. There is. In the above-described video data reproducing device 20, by repeatedly reproducing the recording medium 21 and appropriately switching the distribution destination channel of the data distributing unit 23,
Video data as shown in FIG. 8 can be output. Then, the video data shown in FIG.
If it is divided into A, B, and C periods of seconds,
One program that is shifted by 3 seconds is sequentially output to these three channels, and the above-described operation is possible. That is, the video data A at the closest time to the output request of this program generated at any time.
By outputting the video data of the channel in which 0 is reproduced, the video data can be output in response to the request. The video data reproducing apparatus of the present invention may employ such an operating method.

Further, in the video data recording apparatus, the apparatus for supplying the source video data is the VTR apparatus in the present embodiment, but any data supply means other than the VTR apparatus may be used. In some cases, it may be transmitted and input by a transmission line. Further, as the encoding method and the decoding method of the video data, the contents of the dummy data, the interface of the recording medium, etc., any suitable one may be used regardless of the present embodiment.

[0046]

According to the present invention, the video data is recorded so that the data amount can be easily controlled at the time of reproduction by the simpler recording circuit and its control circuit and the data can be supplied to the NOVD system. A video data recording device can be provided. Further, it is possible to provide a video data reproducing device for reproducing video data so that the data amount can be easily controlled by a simpler recording circuit and its control circuit and the data can be supplied to the NOVD system.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a video data recording device according to an embodiment of the present invention.

FIG. 2 is a diagram showing the amount of encoded data for each program,
(A) is a figure which shows the data amount for every GOP, (B) is a figure which shows the total of the encoding amount of each program.

FIG. 3 is a diagram showing a state in which dummy data is added to variable length coded video data to make it a fixed length and the data is recorded on a recording medium.

FIG. 4 is a block diagram showing a configuration of a video data reproducing device according to an embodiment of the present invention.

5 is a diagram showing an example of reproduction output of the video data reproducing device shown in FIG. 4, and is a diagram showing a state in which three programs are simultaneously output to three channels.

FIG. 6 is a block diagram showing a configuration of a modified example of the video data recording device according to the embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a modified example of the video data reproducing device according to the embodiment of the present invention.

FIG. 8 is a block diagram of the video data reproducing device shown in FIG.
FIG. 6 is a diagram showing a state in which the video data of 3 is shifted by 3 seconds and simultaneously output to three channels.

FIG. 9 is a diagram showing a state in which video data is recorded on a recording medium in units of video data for each predetermined time.

FIG. 10 is a diagram showing a state in which video data is recorded on a recording medium in units of video data of a predetermined data amount.

[Explanation of symbols]

 10 ... Video data recording apparatus 11 ... VTR section 12 ... MPEG2 encoder section 13 ... FIFO section 14 ... Dummy data inserting section 15 ... Multiplexer 16 ... SCSI interface 17 ... Recording medium 18 ... Controller 20 ... Video data reproducing apparatus 21 ... Recording medium 22 ... SCSI interface 23 ... Data distribution unit 24 ... Data output unit 25 ... FIFO 26 ... MPEG2 decoder 27 ... Video I / F 28 ... Controller 29 ... Dummy data separation unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H04N 7/13 Z

Claims (5)

[Claims] 1. A video data recording device for recording data for use in a system for simultaneously transmitting a plurality of types of video data to a plurality of channels, wherein a variable length encoding is performed on each of the plurality of types of video data. Long coding means and complementary data addition for adding arbitrary complementary data to each data so that the data for a predetermined time of each of the variable length coded video data has a predetermined predetermined data length And a data recording means for continuously and accessiblely recording, in a recording medium, data of the predetermined data length of each of the plurality of types of video data, which data are simultaneously transmitted in the system. Data recording device. 2. The video data recording apparatus according to claim 1, wherein the complementary data is dummy data having a predetermined value. 3. A system for simultaneously transmitting a plurality of types of video data to a plurality of channels, wherein the plurality of types of video data to be transmitted simultaneously are variable length coded and data for a predetermined time is predetermined. A video data reproducing device for reproducing a recording medium, to which complementary data is added so as to have a data length, and the data of the predetermined data length transmitted at the same time is continuously accessible and recorded, Data reproducing means for simultaneously reading the data of the predetermined data length of each of the plurality of types of video data from the recording medium at least within the predetermined time, and separating the complementary data from the read data. And a video data reproducing device having data output means for outputting the video data separately for each type. 4. The data output means separates the complementary data from the read data, and the complementary data separating means separates the complementary data for each type of the video data. The video data reproducing device according to claim 3, further comprising a data distributing means for distributing. 5. The data output means distributes each of the read data for each type of the video data, and the variable length coding for each of the distributed video data. The video data reproducing apparatus according to claim 3, further comprising video data extracting means for decoding the data and extracting only the video data.