JP2000244864A - Digital magnetic recording / reproducing device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To enable a user to confirm a search video in a digital video recording / playback using MPEG without significantly changing the D-VHS format. SOLUTION: Three ECs arranged on one track
One block on the lower side of the tape of the C block is allocated to a blank portion, and the upper two blocks are allocated to an MPEG data portion. The MPEG data part can use the conventional error correction, so the basic MPE
Recording and reproduction of the G2 signal can be ensured. In a blank portion where no MPEG data is recorded, I-picture data corresponding to a still image synchronized with a video recorded by MPEG is recorded in accordance with the trajectory of a tape head when fast-forwarding and rewinding playback (commonly called search playback). In a state where they are arranged in a state, only the relevant data is taken out, and still images are sent out at regular intervals in synchronization with the video recorded by MPEG at the time of the search and reproduced, so that the contents recorded on the tape can be visually checked. You can check.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital recording / reproducing apparatus, and more particularly, to a digital recording / reproducing apparatus using a VHS mechanism as it is and
The present invention relates to a D-VHS system that performs digital video recording and playback using EG2.

[0002]

2. Description of the Related Art An MPE is used by utilizing a VHS mechanism as it is.
In a D-VHS system that performs digital video recording / playback using G2, video cannot be played back in fast-forward and rewind playback normally performed in VHS.

In a system for recording data compressed by MPEG2 using the mechanism of a magnetic recording / reproducing apparatus such as a VHS as it is, when a digital signal is recorded on a tape, an ECC block for error correction is basically used. ,
Data shuffling is performed for a plurality of ECC blocks collectively, and error correction can be performed satisfactorily with respect to data loss that occurs when recording and reproducing on a tape. The system is generally a D-VHS (Digital V
HS) has been proposed in a format in which an MPEG2 data stream can be recorded and reproduced.

[0004] When an MPEG2 signal is recorded by the system, since the data is dispersed and scattered in order to perform error correction as is well known, the video is checked while fast-forwarding and rewinding the tape. Video playback, commonly called search playback, cannot be performed. For this reason,
In order to search for a required video from the middle of the tape, it is necessary to stop the running of the tape each time and set to a normal reproduction mode, which is very complicated.

Hereinafter, this conventional technique will be described in more detail with reference to the drawings. FIG. 6 shows the current D-VHS ECC.
FIG. 6A is a diagram showing a code configuration of the current D-.
FIG. 6B shows a block configuration of ECC formatted by VHS, and FIG. 6B shows E in a format for transmitting a transport stream of an MPEG2 signal implemented by D-VHS by two sync blocks.
It is a figure which shows the structure of the sync block of CC. As shown in the figure, the EC formatted in the current D-VHS
The block configuration of C is 112 bytes x 112 bytes of E
The structure of the CC is fundamental, and MPEG2 data is packetized in two sync blocks, and an inner parity is added to the packet. D-
In a format for transmitting a transport stream of an MPEG2 signal implemented by VHS using two sync blocks, data corresponding to 188 bytes of the transport stream is transmitted by two sync blocks.

FIG. 7 shows a formatted D-VHS.
It is a figure showing a tape pattern of data of a method. As shown in the figure, the data is arranged at a place where the data is determined according to the following equation (1) for each sync block over six tracks.

[0007]

(Equation 1)

FIG. 8 shows an arrangement pattern on a tape for shuffling of D-VHS data. Assuming that data recording starts from the arrow, the order of the first MPEG2 data starts from the 0th of L1 as shown in the figure, such as 0, 1, 2, 3. The data is arranged in the sync block of R3, and thereafter data is arranged on all six tracks while data sequentially moves on each track. The array of the data is given by equation (1)
It is represented by Obviously, with such an arrangement of data, it is impossible to transmit the video while fast-forwarding the tape.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and is a significant improvement over the error correction system and shuffling system employed in the current D-VHS format. It is an object of the present invention to enable the appearance of a video by search and to confirm a video written on a tape even in the recording and reproduction of a digital video according to MPEG2 without changing to the above. .

[0010]

SUMMARY OF THE INVENTION The present invention provides
As an arithmetic expression for shuffling MPEG2 data into six tracks, expression (1) used in the conventional method is changed to the following expression (2).

[0011]

(Equation 2)

Equation (1) means that data is shuffled and arranged on six tracks. That is, the input MP
By dispersing the data of the EG2 signal according to a certain rule, error correction can be performed more reliably even if data is lost. On the other hand, in the arithmetic expression of the present invention, s in the expression (1) is changed from s = 0 to 2 → s = 0 to 1, and S is S = s + 3 × i → S = s + 2 × i or S = 112 + (s + 2 × i The physical meaning means that a data array composed of three ECC blocks in one track is arranged in two ECC blocks in the conventional method. I have.

This means that no data is allocated to one of the three ECC blocks on one track, on the upper or lower side of the tape, and the function is the same. Therefore, a portion where normal MPEG2 data is not recorded can be set on the tape. And in that place,
By recording the MPEG-2 I-pictures that can compose one screen so as to be divided and arranged according to a certain rule, only the I-pictures from the area are traversed during fast-forward and rewind playback. By taking it out, it is possible to check the information of the video recorded on the tape intermittently.

According to the first aspect of the present invention, three tracks are stored in one track.
The helical scan method has a data error correction structure by ECC (Error Correction Control), and has a structure in which the tracks are shuffled as a set of six tracks to complete the data arrangement. In a magnetic recording / reproducing apparatus, MPEG2
(Moving Picture Experts Group) is processed into 18 ECCs composed of the 6 tracks.
When shuffling a block to arrange the data of the digital signal, three Es provided in one track are used.
One ECC block in the CC block has a normal M
PEG2 data is not recorded, and I picture data of MPEG data is arranged and recorded according to a certain rule, so that even if the tape is fast-forwarded, the I picture data is intermittently read and decoded. Is a digital magnetic recording / reproducing apparatus capable of confirming a video signal at regular intervals.

According to a second aspect of the present invention, there is provided the digital magnetic recording / reproducing apparatus according to the first aspect, wherein the digital signal processed by MPEG2 is composed of the six tracks, and
When arranging data by shuffling the ECC blocks, three ECC blocks provided in one track are used.
One ECC block is replaced with a normal MPEG
2 is a blank portion where no data is recorded, and the I picture data of MPEG2 data is
By arranging and recording, even if the tape is fast-forwarded, video data can be confirmed at regular intervals by intermittently reading and decoding the I picture data.

According to a third aspect of the present invention, there is provided the digital magnetic recording / reproducing apparatus according to the first or second aspect, wherein the I picture data is further compressed in the blank portion than the data obtained by an ordinary MPEG2 encoder. By reducing and recording still image data by performing a process equivalent to screen division, still image data can be effectively extracted from data that is small during search reproduction.

According to a fourth aspect of the present invention, in the digital magnetic recording / reproducing apparatus according to the third aspect, when the search reproduction is executed, the still image data recorded in the blank portion obtained by the search reproduction is converted to a normal screen. On a smaller screen,
It is intended to be displayed.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A digital magnetic recording / reproducing apparatus according to the present invention will be described in detail with reference to FIGS. FIG. 1 is a diagram showing an array of data according to the present invention. One block (open portion) below the tape of the three ECC blocks arranged in one track is assigned to a blank portion, and two upper blocks (shaded portion) are assigned to an MPEG data portion. The arrangement of the data can be realized by using the above equation (2). Therefore, this M
Since the conventional PEG data portion can use the same error correction, recording and reproduction of a basic MPEG2 signal can be secured with a slight change. Then, one of the three ECC blocks arranged in one track
The MPEG-2 data is not recorded in the C block.
It records and reproduces MPEG2 signals only in the data area,
Processing such as error correction at the time of reproduction can be performed without any problem.

A blank portion in which MPEG2 data is not recorded can be used as a new data area. In this area, a blank image corresponding to a still picture synchronized with a video recorded in MPEG, for example, MPEG2 Are arranged in a state corresponding to the trajectory of the tape head at the time of fast forward and rewind reproduction (commonly called search reproduction), and only the data is taken out, so that the data recorded in MPEG at the time of search is obtained. If a still image is transmitted at a fixed interval and reproduced in synchronization with the video, the contents recorded on the tape can be visually checked.

FIG. 2 shows that the above-mentioned blank portion of the present invention has an MP.
An example of an arrangement in which data corresponding to an I picture of EG2 is divided into a plurality of pieces and arranged is shown. FIG. 3 shows an example of division of an I-picture screen corresponding to a still image. In this method, each signal obtained by decomposing one screen into eight (A to H) as shown in FIG. 3 is arranged every 13 tracks as shown in FIG. That is, the blank part is divided into approximately two equal parts, and video data of two (A, B) of the eight divided videos is arranged in the area. In this method, an I picture corresponding to an MPEG still image is divided at the lower side of a tape, signals are arranged in a data area corresponding to a sync block shown in FIG.
Are added to form a regular sync block.

FIG. 4 shows a specific trajectory of a head for reproducing data recorded on a tape when search reproduction is performed. The data of the I picture corresponding to the still image synchronized with the video data compressed by MPEG is divided into the above-described sync blocks, and is arranged in a portion corresponding to the locus of the reproducing head. By doing so, in the normal reproduction, the area of the MPEG data corresponding to the shaded area shown in FIG. 1 is reproduced, and the data in the blank part is reproduced according to the instruction of the data recorded in the header. Not done.

In such a state, when search playback is performed, as can be seen from FIG. 4, the playback head can take out data corresponding to the I picture, thereby intermittently producing a still image. It is possible to check the video signal recorded on the tape while performing search reproduction. That is, the R head reproduces data corresponding to A and B of the still image arranged in the blank portion,
The head reproduces data corresponding to C and D. At this time, by setting the reproducing head wider than the track pitch normally recorded, more accurate data can be obtained as a reproducing signal. In this embodiment, a search speed of 13 times is shown, but it is apparent that reproduction at the time of search can be obtained at other double speeds by re-arranging the arrangement of still images for recording. .

FIG. 5 shows a basic circuit block diagram of the digital magnetic recording / reproducing apparatus of the present invention. The video input signal is
The input data is converted into a format that can be processed by the MPEG encoder by the input processing circuit 1, and the MPEG2 encoder 2 compresses the video data via the memory 3 (details are omitted). The data compressed by the MPEG2 encoder 2 is
In the shuffling / ECC adding circuit 4, a configuration corresponding to the data array shown in FIG. 4 is constructed on the tape by the data shuffling method represented by the above equation (2).

On the other hand, the I picture compression / ECC addition circuit 5 further compresses the data corresponding to the still picture of the I picture from the MPEG2 encoder and inserts the signal with the ECC added into the blank part as shown in FIG. To do. The method uses the formatter 6 to convert the data in FIG.
Format into a data array as shown in. At this time, the I picture is simultaneously configured in the I picture compression process in the I picture compression / ECC adding circuit 5 so as to divide one screen into a plurality of screens as shown in FIG.

The signal is supplied to the REC / PB PLL circuit 7
Is recorded on the tape via the head 8. The signal recorded on the tape is transmitted to the head 8 and the REC / PBP
The data is reproduced by the LL circuit 7, and the normal reproduction is separated by the deformatter 9 into the above-described MPEG signal and the signal of the blank portion. Therefore, the data of the ordinary MPEG signal is restored so that the MPEG can be decoded by the deshuffling / ECC circuit 10, and the MPEG decoder 13 demodulates the data into a video signal before being encoded through the memory 12 via the memory 12.

On the other hand, in the search reproduction, the operation of the circuit is stopped, the portion recorded in the blank portion on the tape is extracted by the deformatter 9, and the I picture / ECC circuit 14 corresponds to the above-described still image. Data to be stored in the memory 15
To restore the divided still image data into an amount equivalent to one video data. The restored data is I
Demodulated by the picture decoder 16 via the memory 17.

The output processing circuit 18 switches between normal reproduction and search reproduction, and produces a video signal according to the broadcast. In addition, since the data obtained by compressing the I-picture has a shortage of data to form a video, when decoding the I-picture, the video output is converted to a so-called thumbnail image smaller than a normal video screen through a memory. It is also possible to send out via processing.

[0028]

According to the present system, the contents recorded on the tape cannot be confirmed by the search reproduction in the related art. However, according to the present invention, the contents recorded intermittently on the tape are not reproduced. The effect is enormous because it can be confirmed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a data arrangement pattern of a tape used in a digital magnetic recording / reproducing apparatus of the present invention.

FIG. 2 is a diagram illustrating an example of an arrangement of recording data in a blank portion.

FIG. 3 is a diagram showing an embodiment of a still image dividing method.

FIG. 4 is a diagram showing a signal array and a track of a head during search reproduction.

FIG. 5 is a block diagram of a digital magnetic recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 6 is a diagram illustrating a current D-VHS ECC code configuration.

FIG. 7 is a diagram showing a tape pattern of D-VHS data.

FIG. 8 is a diagram showing a tape pattern for shuffling D-VHS data.

[Explanation of symbols]

1: input processing circuit, 2: MPEG2 encoder, 3, 1
1, 12, 15, 17 ... memory, 4 ... shuffling / E
CC addition circuit, 5 ... I picture compression / ECC addition circuit, 6 ... Formatter, 7 ... REC / PB PLL circuit, 8 ... Head, 9 ... Deformatter, 10 ... Deshuffling / ECC circuit, 13 ... MPEG decoder, 14 ...
I picture ECC circuit, 16 ... I picture decoder, 18 ... output processing circuit.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5C018 CA03 CA05 FB03 HA00 JC04 LA03 NA01 5C053 FA22 GB01 GB15 GB18 GB38 HA24 KA03

Claims (4)

[Claims] 1. One track has a data error correction structure based on three ECCs (Error Correction Control), and the tracks are shuffled as one set of six tracks to arrange data. MPEG2 (Moving Pictu) in a helical scan digital magnetic recording / reproducing device with a structure to complete
re Experts Group) shuffles the digital signal processed into the 18 ECC blocks composed of the 6 tracks, and arranges the data of the digital signal when three ECCs provided in one track are arranged. Normal MPEG2 data is not recorded in one ECC block of the blocks, and I picture data of MPEG data is arranged and recorded according to a certain rule, so that even if the tape is fast-forwarded, By intermittently reading and decoding the I picture data,
A digital magnetic recording / reproducing apparatus characterized in that video signals can be confirmed at regular intervals. 2. The digital magnetic recording / reproducing apparatus according to claim 1, wherein data is arranged by shuffling a digital signal processed by MPEG2 into 18 ECC blocks composed of said 6 tracks. In the three ECC blocks provided in one track,
One ECC block is a blank portion in which normal MPEG2 data is not recorded, and I-picture data of MPEG2 data is arranged and recorded according to a certain rule, so that even if the tape is fast-forwarded, the I-picture of the I-picture can be recorded. A digital magnetic recording / reproducing apparatus characterized in that video signals can be confirmed at regular intervals by intermittently reading and decoding data. 3. The digital magnetic recording / reproducing apparatus according to claim 1, wherein data of the I picture in the blank portion is reduced to a data amount further compressed than data obtained by a normal MPEG2 encoder, and a still image is recorded. A digital magnetic recording / reproducing apparatus characterized in that data is processed by a process corresponding to screen division and recorded, so that still image data can be effectively extracted from data that is small during search reproduction. 4. The digital magnetic recording / reproducing apparatus according to claim 3, wherein, when search reproduction is performed, still image data recorded in a blank portion obtained by search reproduction is displayed on a screen reduced from a normal screen. And a digital magnetic recording / reproducing apparatus for displaying.