JPH08111842A - Video data recording system - Google Patents

Abstract

PURPOSE: To provide a video data recording system in which a data structure imparted at recording is completely reproduced even in the case of special reproduction in a digital VTR. CONSTITUTION: While recording tracks NT for usual reproduction data are formed on a tape 23, a recording track TT for special reproduction data is formed between the tracks NT. The usual reproduction data are made up of data of in-frame coding image and data of inter-frame prediction coding image and the special reproduction data are made up only the data of in-frame coding image. Furthermore, the special reproduction data are formed by adding an inner code and an external code for error correction to the video data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital video tape recorder for recording and reproducing a video signal as digital data on a tape, and more particularly to a video data recording system capable of special reproduction such as high speed reproduction. is there.

[0002]

2. Description of the Related Art In the ATV (Advanced Television) standard proposed as a next-generation digital broadcasting system in the United States, MPEG (Moving Picture Image) which is an international standard for image compression is used as a compression method when transmitting image data.
Coding Experts Group) method is about to be adopted.

The MPEG system employs motion-compensated prediction, DCT (discrete cosine transform), and variable length coding in data coding. As shown in the frame structure of FIG. Depending on the prediction mode, I (intra
-coded) picture, P (predictive coded) picture, B
(bi-directionally predictive coded) pictures are classified into three types. The I picture is an intra-frame coded image, the P picture is an inter-frame predictive coded image predicted from a temporally preceding frame, and the B picture is an inter-frame predictive coded image from preceding and following frames.

A data hierarchical structure of an image in the MPEG system is shown in FIG. It is configured as follows from the lower layer. (Block layer) Blocks are 8x adjacent to each other in luminance or color difference.
It consists of 8 pixels, and DCT is executed in this unit. (Macroblock Layer) A macroblock is composed of four adjacent luminance blocks and two chrominance blocks Cb and Cr at the same position on the screen, for a total of six blocks. (Slice Layer) A slice is composed of a plurality of macroblocks that are continuous in the scanning order of an image. (Picture layer) A picture consists of multiple slices,
Form one image. It is classified into the above-mentioned I picture, P picture, and B picture depending on the encoding format. (GOP Layer) A GOP (Group of Pictures) is composed of one or a plurality of I pictures and 0 or a plurality of non-I pictures. (Video Sequence Layer) A video sequence is composed of one or a plurality of GOPs having the same image size and image rate.

On the other hand, HD (High Definition) digital V
The CR Council is studying standardization of a digital video tape recorder (digital VTR) for recording and reproducing a video signal as digital data. Here, it is conceivable to record the data of the ATV standard (ATV signal) which is image-compressed by the above-mentioned MPEG system on the magnetic tape. FIG. 16 shows a standard signal recording format in a digital VTR. Tape as shown
The track formed on the signal surface of (23) is composed of an ITI area including insert data and track information, an audio data area, a video data area, and a subcode data area. The recording speed is 300 tracks per second, and one frame of image is recorded using an average of 10 tracks.

Data is recorded in units called sync blocks, and 135 data is recorded in a video data area of one track.
Sync blocks can be recorded. Video data is shown in Figure 1.
As shown in FIG. 7, it is treated as a block of 135 × 77 bytes, and an error correction code consisting of an inner code and an outer code, sync data, and ID data are added to the data block, and these data form one data block. It is recorded on the track. The inner code is mainly used for detecting and correcting random errors, and the outer code is mainly used for detecting and correcting burst errors. One sync block is recorded in the order of sync data, ID data, video data, and error correction code.

Since the macroblocks in the data layer shown in FIG. 15 are not constant in code length and are recorded mixedly with the upper layer, the sync block and the recorded macroblock are different from each other. There is no fixed relationship. That is,
The position on the screen determined by the macro block and the position on the recording track pattern determined by the sync block are irrelevant.

When the magnetic tape recorded in this way is run at a speed different from that at the time of recording to perform special reproduction such as high-speed reproduction, the head scans across a plurality of tracks, and therefore the MPEG system is used. The data of is not obtained continuously and becomes fragmentary. As described above, since P pictures and B pictures in the MPEG bit stream are inter-frame predictive coded images, even if they are acquired in pieces, the images cannot be reconstructed.

That is, the special reproduction picture can be reconstructed based only on the I picture which is the intra-frame predictive coded picture, and in the reconstruction of the I picture, the I picture distributed on the track can be reconstructed. You need to get all the data in order.

Therefore, as a special reproduction method in the digital VTR, the journal "Intern" issued in October 1993 was published.
“A Recording Metho” from “ational Workshop On HDTV '93”
d of ATV data on a Consumer Digital VCR ”is known.

In this method, a specific area is provided in the video data area of each track, and the I picture data is recorded as the special reproduction data in the specific area in addition to the normal reproduction data. . The reason why such a recording method is possible is that the data rate of the ATV signal is about 19.3 Mbps, while the HD digital VC is
This is because the one-track video data area based on the standards of the R Council can be recorded at a data rate of about 24.9 Mbps, so that an area corresponding to about 5.6 Mbps remains as a recordable area.

Specifically, as shown in FIG. 18, a data area NPA for normal reproduction is provided in the video data area on one track, and the front, center and rear areas on the track are divided into three areas. Data area TP for special playback
A is provided. A total of 32 SBs of the video data area 135SB (sync block) of one track is allocated to the three special reproduction data areas TPA.

In this case, the trick play data is assigned by the method shown in FIG. First, from the MPEG bit stream, I picture macroblock A,
B, C, ... are extracted and data strings A ′, B ′,
Get C '... Here, the code lengths of the encoded macroblocks are different. Then, the data blocks A ′, B ′, C ′, ...
1, SB2, SB3, ... At this time,
Since the sync block has a constant code length, each sync block and the assigned macro block do not have a fixed relationship, and one macro block extends over a plurality of sync blocks.

Then, as shown in FIG. 18, the same special reproduction data is recorded on the same number of tracks as the maximum double speed number n set in the special reproduction. For example, as shown in the figure, n
= 5, the same data is recorded in the special reproduction data area TPA of five consecutive tracks.

Further, the data is updated in units of 5 tracks, and this is repeated a plurality of times (m times) to record all the I picture data by 5 × m tracks.
According to the above-mentioned recording method, if the reproduction speed is 5 times or less, 5 × m tracks will be recorded once every 5 tracks for a total of m.
By scanning twice, it is possible to acquire all the video data of the I picture.

[0016]

However, in the above method, the special reproduction data area TPA is divided and arranged on one track even if all the video data of the I picture can be acquired. The data structure of FIG. 17 cannot be completely restored depending on the data acquired from these areas. Therefore, error detection and error correction by the inner code and the outer code are impossible, and there is a problem that the image quality of the special reproduction image is not guaranteed. An object of the present invention is to provide a video data recording system that can completely reproduce the data structure given at the time of recording even during special reproduction.

[0017]

According to the video data recording method of the present invention, the recording tracks of the normal reproduction data are formed, and the recording tracks of the special reproduction data are formed between these tracks. It is a thing.

Specifically, one or a plurality of predetermined recording tracks of special reproduction data are repeatedly formed at regular intervals for a predetermined plurality of normal reproduction data recording tracks.

The normal reproduction data is composed of intra-frame coded image data and / or inter-frame predictive coded image data, and the special reproduction data is composed of only intra-frame coded image data. Is.

The special reproduction data is a video data recording system in which an inner code and an outer code for error correction are added to the video data.

Further, the special reproduction data is a video data recording system in which sync data and ID data are added to the video data.

Further, the ID data is a video data recording system including frame identification data.

Furthermore, the special reproduction data is a video data recording system in which the position on the tape and the position on the screen are recorded in correspondence with a predetermined relationship.

[0024]

In the video data recording system according to the present invention,
A recording track dedicated to special reproduction data is formed separately from the recording track of normal reproduction data. For example, multiple
Of the (k) tracks, (k-1) are the recording tracks for the normal reproduction data and one is the recording track for the special reproduction data. At this time, when the video data supplied from the outside for recording is an ATV signal and the ATV signal is recorded on the tape in the standard signal recording format of the digital VTR, the data rate of the ATV signal is about 19.
The data rate of the data recording by the digital VTR is about 24.9 Mbps, whereas the difference between both data rates is about 5.6 Mbps, that is, two tracks in about 9 tracks. Track is left as a recordable area. So in this case,
The special reproduction data can be recorded on two of the nine tracks or one of the five tracks.

In the case of an ATV signal which has been subjected to data compression by the MPEG system, the normal reproduction data is the data of the intra-frame coded image (I picture) and the inter-frame predictive coded image (P picture, B picture). Composed of both data. On the other hand, the special reproduction data is composed of only the data of the intra-frame coded image (I picture) to simplify the circuit structure.

Further, like the normal reproduction data, the special reproduction data also maintains the standard signal recording format in the digital VTR, that is, an inner code and an outer code for error correction are added to the video data. At the same time, the data structure with the sync data and the ID data added is continuously recorded on one track.

When recording data for special reproduction, k consecutive tracks are regarded as one cycle and a plurality of times (n cycles)
Record the same data. The n cycles are determined according to the maximum allowable double speed of special reproduction. Then, the n-cycle track is set as one block, the data is updated for each block, and this is repeated a plurality of times (m times), and all the I picture data is recorded by the m blocks. Here, the block number m is a large value when the information amount of one special reproduction image is defined and high image quality is achieved. Therefore, during special reproduction, head scanning is performed a plurality of times on the n special reproduction tracks in one block to obtain all the same special reproduction data recorded on these tracks. For example, it is possible to completely restore the standard-format special-playback data originally recorded on one track. Then, by the same reproduction operation for m blocks, special reproduction data for one frame is obtained, and one image can be reconstructed.

Since the data acquired from n tracks in one block includes all the data for one track, error detection is performed using the inner code and outer code included in these data. And error correction can be performed.

If the frame identification data is recorded for each of the above-mentioned m blocks as a part of the ID data, one frame is composed of only the data in the same frame by detecting the frame identification data during special reproduction. It becomes possible to configure.

Furthermore, when recording special reproduction data,
If the position on the tape and the position on the screen are recorded in correspondence with a predetermined relationship, the data on the same screen of different frames is used even when the scan during the special reproduction spans adjacent frames. This makes it possible to reconstruct one image.

[0031]

According to the video data recording system of the present invention, the special reproduction data is recorded on the tape in track units. Therefore, during special reproduction, the data structure added in track units at the time of recording is completely reproduced. You can

[0032]

[Example] Hereinafter, ATV standard data is converted to HD digital V
An embodiment of recording by a digital VTR based on the standards of the CR Council will be specifically described with reference to the drawings.

FIG. 1 shows a track pattern formed on the tape (23), in which a recording track NT for normal reproduction data and a recording track TT for special reproduction data are repeatedly formed. In the embodiment of FIG. 1, 5 consecutive
One book out of the five is a special reproduction track TT, and the remaining four are normal reproduction tracks.

On the normal reproduction track NT, I pictures, P pictures and B pictures encoded by the MPEG system shown in FIG. 14 are recorded. On the other hand, only the I picture is recorded on the special reproduction track TT. The special reproduction track TT has the same format as the standard format of the normal reproduction track shown in FIGS. 16 and 17, and the special reproduction data, that is, the video of the I picture is utilized by using the video data area therein. Data is recorded. Similar to the normal reproduction data, sync data and ID data are added to the video data in addition to the inner code C ₁ and the outer code C ₂ . The inner code C ₁ is a (85,77) Reed-Solomon code, and the outer code C ₂ is a (149,138) Reed-Solomon code.
Therefore, if one special reproduction track is reproduced,
7 standard format data will be completely restored.

As shown in FIG. 1, one cycle consisting of one special reproduction track and four normal reproduction tracks is repeated a plurality of times (n times) as shown in FIG. 2 to form one block. To be done. The same special reproduction data is repeatedly recorded on each of n special reproduction tracks included in one block. Here, the number of repetitions n is
Determined according to the maximum speed of special playback. For example, 1
When one cycle is composed of seven special reproduction tracks and six normal reproduction tracks, the cycle is repeated at least 14 times assuming that the maximum double speed is 6 times.

The above blocks are repeatedly formed a plurality of times (m times) as shown in FIG. 3 while updating the trick play data, and the data for one frame of the I picture is recorded by these m blocks. To do. Then, by further forming m blocks, the video data of a plurality of frames A, B, C, ... Of the I picture is recorded.

As shown in FIG. 3, frame identification data "0" or "1" is added to m blocks which should form one frame, and is recorded on the tape as the ID data. By this, it is possible to identify whether the data reproduced from the tape is the data included in the same frame or the data in the adjacent frame.

In FIG. 4, one recording track for special reproduction data and six recording tracks for normal reproduction data 2 to 7 are repeatedly formed on the magnetic tape, and the azimuth angle is provided on the rotary head cylinder. 180 degrees facing different 2
The case where the magnetic tape is reproduced by the heads (A head, B head) is shown. Here, a recording cycle for these seven tracks is repeated 14 times to form one block. The same trick play data is recorded on 14 trick play tracks in the same block.
Signals are recorded on adjacent tracks by heads having different azimuth angles, and in this process, special reproduction tracks are alternately recorded by heads A and B.

At the time of special reproduction, the reproduction speed is set to 6 times, and a scanning locus extending over seven tracks is formed as shown in the figure. When the first scan is performed by the B head, data is reproduced from the first area of the special reproduction track in the first cycle I ₁ by the scanning locus (1B) as shown by hatching. Be done. The second scanning is performed by the A head, and the scanning locus (2A) reproduces data from the second area of the special reproduction track in the second cycle I ₂ . Hereinafter, similarly,
Data reproduction from the special reproduction track progresses, and data is reproduced from the last sixth area of the special reproduction track in the sixth cycle I ₆ by the sixth scanning locus (6A). The same special reproduction data is recorded on these special reproduction tracks, and the first to sixth areas I _{1 to} I ₆ described above partially overlap each other and are displaced in the track direction. Therefore, it is possible to obtain all the data for one trick play track from these areas.

Next, with reference to FIG. 5, an allocation method at the time of recording the special reproduction data will be described. First, as shown in FIG. 5A, I
The macroblocks A, B, C, ... Of the picture are extracted and the data strings A ′, B ′, C ′, ... Shown in FIG.
・ Get Here, the code lengths of the encoded macroblocks are different.

Next, each data string A ', B', C ', ...
・ The code length is controlled so that becomes a constant code length of 77 bytes. Then, the data strings A ″, B ″, C ″, ... Controlled to have a constant code length are sequentially arranged in the video data area of the sync blocks SB1, SB2, SB3 ,. At this time, if the number of the sync block in one frame is recorded in the ID area, it is possible to specify at which position on the screen the reproduction data is during reproduction.

As described above, since one macro block is assigned corresponding to one sync block,
The position of the data on the screen and the position of the track have a fixed relationship. Therefore, it is possible to reconstruct an image of a specific portion on the screen from only one sync block data. It should be noted that the allocation method only needs to have a fixed relationship between the macroblock and the sync block.
A method of allocating a plurality of macro blocks to one sync block or a method of allocating one macro block to a plurality of sync blocks can also be adopted.

FIG. 6 shows a pattern diagram in which only special reproduction tracks in one block of this embodiment are collected. In the figure, the vertical direction is the track direction, and the horizontal direction is the tape running direction. For the sake of convenience, the special reproduction track of each cycle is drawn so as not to be oblique with respect to the tape but orthogonal to the tape running direction. The alphabet in the track indicates a frame, and the subscript indicates the block number on the left side and the sync block number on the right side. The number of sync blocks is actually 135, but for convenience, it is set to 10. As shown in the figure, the data of the same sync block number of the special reproduction tracks in the same block are all the same.

FIG. 7 shows the data arrangement of the special reproduction track in each block included in each block in the same frame, and FIG. 8 shows the data arrangement of the special reproduction track in each block in a different frame. There is. As shown in the figure, the data of one frame (one I picture) consists of m kinds of special reproduction tracks having different data, and one kind of special reproduction track having different data is plural.
Recording is repeated n times with (x) books as one cycle.

On the other hand, the normal reproduction data is input M
The PEG bit stream is divided into 77 bytes without limitation and assigned to the video data area of the sync block.

A case where the recording pattern of FIG. 4 (one in seven special reproduction tracks) is reproduced at 6 × speed will be described. Scanning by two 180-degree facing heads is as shown in FIG. In the first scan by the B head, the data a
₁₀ and a ₁₁ are obtained, and data a ₁₁ , a ₁₂ and a ₁₃ are obtained in the second scanning by the A head. After that, the third,
By scanning the fourth, fifth, ..., All the data _a00 to _a09 of the special reproduction track within one block are obtained. These data correspond to specific positions on the screen shown in FIG. That is, the 2-digit number on the screen corresponds to the 2-digit subscript of the sync block in FIG. here,
The data of one track corresponds to a macroblock for one horizontal row on the screen.

Therefore, since the reproduced data from one sync block can reconstruct the image independently, if all kinds of sync blocks in which the data in the same frame are recorded can be reconstructed, one screen is reconstructed. I can. Further, even if not all types of sync blocks can be acquired, the screen can be reproduced to some extent according to the number of sync blocks acquired, so that the screen is easier to see than in the past. Further, as shown in FIG. 8, when the data arrangement is such that the position of the screen and the data position of the sync block are the same between frames, the tape speed is such that one screen is composed of data over a plurality of frames. Will also be easier to choose.

Next, the signal recording circuit shown in FIG. 10 will be described. First, the MPEG bit stream based on the ATV standard is input to the buffer memory (1) and the I picture extracting circuit (2). In the buffer memory (1), the input data is divided into 77-byte units in order to allocate the normal reproduction data for the normal reproduction track NT to the video data area of each sync block, and this is divided into the mixing circuit (3).
Send to.

On the other hand, in the I picture extracting circuit (2), M
From the PEG bit stream, only the I picture of the MPEG system is extracted and divided into a DC component DC and an AC component AC and output. Here, the I picture extracting circuit (2) has
As shown in FIG. 5, data is input in macro block order. In addition, the bit stream for each block of 8 × 8 pixels, which is a unit to which DCT is applied, has a DC component DC first, and then AC components AC are arranged in order from the lowest frequency to the highest frequency. , The code length differs for each macroblock.

In the MPEG system, since predictive coding is performed between blocks, that is, the difference between the DC component of the current block and the DC component of the previous block is coded and transmitted, so that, as it is, The DC component cannot be reproduced from only one macro block. So I
The DC component DC from the picture extracting circuit (2) is supplied to the DC component D for each macroblock by the DC data conversion circuit (21).
Convert the data so that C can be played independently.

In the code length control circuit (4), the code length is controlled so that the total of DC and AC becomes 77 bytes for each macroblock, and the 77-byte data is transferred to the buffer memory (5 ) To. As a result, one macroblock can be assigned to each sync block. In addition, the I picture extracting circuit (2)
A flag is generated once per macroblock during picture extraction. The counter (6) counts the flag for each I picture and outputs it as a macroblock number MB.

The buffer memory (5) comprises two frame memory areas A and B which are parallel to each other. The write address to the buffer memory (5) is controlled by the macro block number, and the reading from the buffer memory (5) is controlled by the timing signal from the timing generation circuit (22). Specifically, the switch S1 is controlled on the basis of the frame identification data, and writing and reading are alternately performed so that when one frame memory area A is in a writing state, the other frame memory area is in a reading state. The output of the buffer memory (5) is supplied to the mixing circuit (3) as special reproduction data for the special reproduction track TT and mixed with the normal reproduction data to realize the track pattern shown in FIG. A series of data for creating is created.

The output of the mixing circuit (3) is added with the error correction code by the error correction code adding circuit (7) and then with the sync data and the ID data by the first data adding circuit (8). . Further, in the second data adding circuit (9) in the subsequent stage,
I, audio data, and subcode are added to form data of a predetermined format shown in FIGS. 16 and 17,
This data is recorded on the tape by the magnetic head.
The error correction code adding circuit (7) includes a memory control circuit (1
RAM (10) controlled by 1) is connected and R
The error correction code is read from the AM (10) and supplied to the error correction code adding circuit (7).

Next, the signal reproducing circuit shown in FIG. 11 will be described. First, the signal reproduced from the tape by the magnetic head is separated from the ITI, the audio data and the sub-code by the first separation circuit (12), and then the second separation circuit (1) at the subsequent stage.
In 3), sync data and ID data are further separated. The video data thus obtained is subjected to known error correction in the error correction circuit (14). The error-corrected data is the normal reproduction data from the normal reproduction track NT and the special reproduction track TT in the third separation circuit (15).
It is separated into special reproduction data from. The normal reproduction data is converted into a constant rate by the first buffer memory (16) and input to the selector (17).

On the other hand, the trick play data is supplied to the second buffer memory (18). The second buffer memory (18) is
Two frame memory areas A and B arranged in parallel with each other are provided, and writing and reading are alternately performed in both frame memory areas A and B at a predetermined cycle. Specifically, the write address of the second buffer memory (18) is controlled based on the sync block number within one frame of the separated ID data. Writing to one of the frame memory areas is performed during a period in which reproduction data from the same frame is obtained as shown in FIG. 3, and when the frame identification data included in the ID data changes, the switch S2 is switched. At the same time, the write operation and the read operation of each frame memory area are switched. As a result, the data reproducing operation of FIG. 3 is realized. The output of the switch S2 is supplied to the MPEG formatting circuit (19). Here, the layers above the macroblock are added to the special reproduction data to make the MP
An EG decoder (not shown) forms a decodable MPEG bitstream and sends it to the second buffer memory (20) at the next stage.

The special reproduction data is stored in the buffer memory (20).
It is converted to a constant rate and is supplied to the selector (17). A selector (17) selects input data according to a mode signal NP / TP for switching between normal reproduction and special reproduction, and outputs it as an MPEG bit stream.

According to the above video data recording method, the following effects can be obtained. Since the special playback data is arranged on the tape in track units, the head configuration and tape playback speed can be selected.
Good special reproduction is possible regardless of the tape feed phase. By recording the positions on the recording track pattern and the positions on the screen in association with each other, the screen can be reconstructed in data block units. By dividing the special reproduction data for one frame into multiple tracks and recording the data of the same frame multiple times repeatedly, more data blocks in the same frame can be acquired, so special reproduction video with a large amount of information can be obtained. Is obtained. By adding the frame identification data to each track, one image can be composed only of the data in the same frame at the time of special reproduction, so that discontinuity on the screen is eliminated and an easy-to-see screen can be obtained. Since special playback data is recorded in track units,
Data error correction can be performed by both the inner code C ₁ and the outer code C ₂ . Therefore, the error correction capability originally possessed by the standard format of the digital VTR can be exhibited without adding a new correction code. Since special playback data is recorded in track units,
Information about data can be easily added. For example, information such as track division of the special reproduction video and the number of repetitions can be recorded as a subcode and used.

In the example of FIG. 4 in which the special reproduction track is formed at a ratio of one to seven, the tape speed at the time of special reproduction in the case of reproducing by two heads 180 degrees opposite to each other is set to 6 times. However, compared to 7 times the basic double speed, 6 times or 8 times that is (7 ± 1) times, 21 times that is (odd times 7 times ± 1) times,
Alternatively, it is possible to set 6/3 times, 8/5 times, etc., which is 1 times the odd number. Also, when forming a special reproduction track at a ratio of 1 in 7 by using 2 double azimuth heads, (14 ±
1) / 2 times 13/2 times or 15/2 times, (14 integer times ± 1) / 2 times 25/2 times, or 1/3 times these integer times 13/4 times, etc. Can be set.

For example, when a special reproduction track is formed at a ratio of one to five and reproduced by two 180-degree facing two heads, the basic double speed is 5 times,
4 times or 6 times which is (5 ± 1) times, 14 times or 16 times which is (odd times 5 times ± 1) times, or 4/3 times or 4/5 times which is 1 / odd of these Can be set. Further, when forming a special reproduction track at a ratio of 1 in 5 by the double azimuth 2 heads, it is (10 ± 1) / 2 times as much as 10 times the basic double speed 9/2. Double or 11/2
It is possible to set a multiple, (integral multiple of 10 ± 1) / 2 times, 19/2 times, or 1/4 times these integer times, such as 9/4 times.

The description of the above embodiments is for the purpose of illustrating the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof. The configuration of each part of the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made within the technical scope described in the claims.

For example, in the example of FIG. 1, during one cycle,
Although one special reproduction track TT is provided for a plurality of normal reproduction tracks NT, as shown in FIG.
A method in which two special reproduction tracks having different azimuth angles are provided adjacent to a plurality (m) of normal reproduction tracks NT, or a plurality of (m) tracks are provided as shown in FIG.
It is possible to employ a system in which two special reproduction tracks having different azimuth angles are provided at intervals with respect to the normal reproduction track NT.

[Brief description of drawings]

FIG. 1 is a diagram showing a track pattern of a video data recording system according to the present invention.

FIG. 2 is a diagram showing a configuration of one block of a track.

FIG. 3 is a diagram showing a relationship between a plurality of blocks of a track and a reproduction frame.

FIG. 4 is an explanatory diagram showing a track pattern and a scanning locus during special reproduction.

FIG. 5 is an explanatory diagram showing a method of allocating special reproduction data.

FIG. 6 is a diagram showing an array of data when only special reproduction tracks in one block are collected.

FIG. 7 is a diagram showing a data arrangement of a special reproduction track for each cycle included in each block in the same frame.

FIG. 8 is a diagram showing a data arrangement of special reproduction tracks in each block in different frames.

FIG. 9 is a diagram showing two-digit numbers given to respective positions on the screen.

FIG. 10 is a block diagram of a signal recording circuit.

FIG. 11 is a block diagram of a signal reproduction circuit.

FIG. 12 is a diagram showing another configuration example of a track pattern.

FIG. 13 is a diagram showing still another configuration example of the track pattern.

FIG. 14 is a diagram showing a frame structure of an MPEG system.

FIG. 15 is a diagram showing a data hierarchical structure in the MPEG system.

FIG. 16 is a diagram showing a data format on a track in a digital VTR.

FIG. 17 is an explanatory diagram showing a block structure of data in a digital VTR.

FIG. 18 is a diagram showing a track pattern according to a conventional recording method.

FIG. 19 is an explanatory diagram showing a method of allocating special reproduction data in a conventional recording method.

[Explanation of symbols]

 TT Special playback track NT Normal playback track (23) Tape (2) I picture sampling circuit (4) Code length control circuit (7) Error correction code addition circuit (19) MPEG formatting circuit

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[Procedure amendment]

[Submission date] December 12, 1995

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 7

[Correction method] Change

[Correction content]

[Figure 7]

Claims (9)

[Claims] 1. A method of repeatedly forming a plurality of tracks on a tape and recording a series of digital video data on these tracks, wherein these tracks are formed while forming recording tracks for normal reproduction data. A video data recording method in which a recording track for special reproduction data is formed between them. 2. The video data according to claim 1, wherein one or a plurality of predetermined recording tracks of special reproduction data are repeatedly formed at a constant interval for a predetermined plurality of recording tracks of normal reproduction data. Recording method. 3. The normal reproduction data is composed of intra-frame coded image data and / or inter-frame predictive coded image data, and the special reproduction data is composed of only intra-frame coded image data. The video data recording method according to item 1. 4. The video data recording system according to claim 3, wherein the special reproduction data is formed by adding an inner code and an outer code for error correction to the video data. 5. The video data recording system according to claim 4, wherein the special reproduction data further comprises sync data and ID data added to the video data. 6. The video data recording method according to claim 5, wherein the ID data includes frame identification data. 7. The video data recording system according to claim 3, wherein the special reproduction data is recorded by associating a position on the tape with a position on the screen in a predetermined relationship. 8. The video data recording method according to claim 7, wherein, in the special reproduction track that is repeatedly recorded, when the data in the track is the same in a certain repeating unit, the data content of the same sync block is the same. 9. The video data recording system according to claim 7, wherein the arrangement of the special reproduction data in units of one frame is the same in units of sync blocks.