JPH0456577A - Digital video signal recording and reproducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a digital video signal recording device and a reproducing device, such as a digital VTR, which encodes a digital video signal with high efficiency and records or reproduces it on a medium.

Conventional technology Conventional digital video signal recording and playback devices include:
For example, there is a rotary head type digital VTR that directly records pixel data without high-efficiency encoding (bandwidth pressure vM).

FIG. 5 shows a block diagram of this conventional digital video signal recording and reproducing apparatus, in which 1 is a first error correction encoder, 2 is a shuffling memory, 3 is a second error correction encoder, and 4 is a block diagram of this conventional digital video signal recording and reproducing apparatus. 5 is a magnetic tape, 5 is a second error corrector, 6 is a deshuffling memory, and 7 is a first error corrector.

In the conventional digital video signal recording and reproducing apparatus configured as described above, during recording, the digital video signal is input to the first error correction encoder 1, an error correction code is added, and the signal is stored in the shuffling memory 2. written.

When reading from the shuffling memory 2, the order of the digital video signal is shuffled pixel by pixel, and the read signal is read out based on the pixel order rearranged by the second error correction encoder 3. An error correction code is added once again and the data is recorded on the magnetic tape 4. During reproduction, the detected signal undergoes error correction by the second error corrector 5 and is written into the deshuffling memory 6. The deshuffling memory 6 performs pixel rearrangement that is the opposite of the pixel rearrangement in the shuffling memory 2 during recording to restore the original pixel order. Thereafter, the reproduced signal undergoes reproduction error correction in the first error corrector 7 and is output as a digital video signal.

The reason why the pixel order is rearranged by shuffling is not only to improve the efficiency of error correction, but also to make it easier to view images played back at high speed on a digital VTR. During high-speed playback on a digital VTR, the head of the rotating drum diagonally crosses the tracks recorded on the tape, as shown in FIG. Therefore, the signals that can be detected will be at discrete locations with respect to the recording pattern. Digital VTRs use only the detected pixels to construct a high-speed playback screen, but when shuffling is applied, the detected pixels are scattered over the entire screen, which has the effect of eliminating unnatural breaks in the screen. be.

Problems to be Solved by the Invention However, when considering a digital VTR that uses high-efficiency encoding, the pixels on the screen are divided into rectangles, and the rectangular units are orthogonally transformed and then variable. The amount of information is compressed by long encoding and collecting information in rectangular units of a fixed valence to form fixed length blocks.

However, when this rectangular unit is shuffled and digitally recorded, unlike shuffling in pixel units, the image when played back at high speed becomes mosaic-like, making it very difficult to see. However, if image information in rectangular units is recorded in the same order without shuffling, the rectangular units in each fixed-length block will be located adjacent to each other on the screen, resulting in a bias in the amount of information and a high-efficiency code. The problem was that the efficiency of conversion did not improve.

In view of the above, it is an object of the present invention to provide a digital video signal recording and reproducing device that achieves both the ease of viewing video during high-speed playback and the efficiency of high-efficiency encoding.

Means for Solving the Problems The digital video signal recording device of the present invention includes a sorting means for rearranging the order of signals in rectangular units obtained by dividing a pixel set on a screen of a digital video signal into rectangles, and a method for changing the signal in rectangular units. variable-length encoding means for long encoding; blocking means for collecting a fixed number of rectangular units to form fixed-length blocks; and simultaneously recording the blocked signals in parallel on a medium using multiple channels. The sorting means is comprised of a plurality of rectangular units located apart from each other on the screen within one block, and the sorting means is configured to simultaneously record data in parallel on a plurality of channels of the recording means. The digital video signal reproducing apparatus of the present invention is characterized in that the rectangular units included in the plurality of blocks to be recorded are rearranged so that they are adjacent to each other on the screen. detection means for detecting digital signals simultaneously recorded on a medium in parallel in a plurality of channels; decoding means for decoding variable length codes in the blocked signals; and rearranging the order of the decoded signals in rectangular units. and a rearrangement means, wherein the rearrangement means is configured such that rectangular units included in the plurality of blocks obtained from the plurality of channels recorded simultaneously in parallel are adjacent to each other on the screen, but the rectangular units included in the plurality of blocks obtained from the plurality of channels recorded simultaneously in parallel are It is characterized in that it is composed of rectangular units located at mutually distant positions on the screen.

Effect of the present invention With the above-described configuration, the present invention devises the rearrangement of digital video signals so that the plurality of rectangular units within a fixed length block are positioned apart from each other on the screen, thereby increasing the efficiency of high-efficiency encoding. Furthermore, rectangular units included in multiple blocks in multiple channels recorded simultaneously on the recording medium in parallel are positioned adjacent to each other on the screen, so that the screen becomes mosaic even during high-speed playback on a digital VTR. It is possible to always reproduce a wide screen area at the same time and make it easier to view.

Embodiment FIG. 1 shows a block diagram of a digital video signal recording and reproducing apparatus in an embodiment of the present invention. This embodiment is a rotary head type digital VTR that divides the screen into rectangular units, performs high-efficiency encoding, and simultaneously records two channels on a magnetic tape.

In FIG. 1, 11 is a formatter, 12 is a sorting memory, 13 is an orthogonal transformer, 14 is a variable length encoder, 1
5 is a block generator, 16 is an error correction encoder, 17 is a magnetic tape, 18 is an error corrector, 19 is a variable-length code decoder, 20 is an inverse orthogonal transformer, 21 is a rearrangement memory, and 22 is a deformator. be. Further, 23 is a recording head, and 24 is a reproducing head, each of which records and reproduces two channels simultaneously in parallel.

The operation of the digital video signal recording and reproducing apparatus of this embodiment configured as described above will be described below.

During recording, pixel data of the digital video signal is formatted in rectangular units on the screen by a formatter 11, and input to a rearrangement memory 12.

FIG. 2 is a diagram showing the division of rectangular units on the screen, and the entire rectangle represents one screen. In this embodiment, as shown in FIG.
, C, D, E, and F. Each area is further divided into rectangular units, and the rectangular units within each area are divided into AR1, ALI, AR2, AL2, .・・・
・Number them like this. In the sorting memory 12, video signals are sorted in rectangular units by API, BRI, CRI, and D.
Rl, ERI, FRI, also ALL, BLI, CLl
, DLI, ELL, FLI, and further, AR2°BR2,
. . . Sort them so that they are taken out one by one from each area. The video signal of each rectangular unit is input to the orthogonal transformer 13, where it is orthogonally transformed encoded using the Hadamard transform or cosine transform method, and then the video signal of each rectangular unit is converted to the information amount by the variable length encoder 14. The data is variable-length coded accordingly. In variable length encoding, the amount of data is determined depending on the amount of information in each rectangle, and high-efficiency encoding is achieved by reducing the overall amount of data. Orthogonal transformation is a means for that purpose. Although the code length of each rectangular unit of information is variable, the block generator 15 collects a plurality of rectangular units of information to form a fixed-length block. In this embodiment, ARl, BRI, CRI, DRI,
Six rectangular units of ERI and FRI constitute one fixed length block, and ALL, BLI, CLI, DLI, and ELL
.

A method is adopted in which one fixed length block is formed by six rectangular units of FLI. Here R and L are 2
Each channel represents the channel identification for each recording head and reproducing head, and each number represents the number of the block recorded for each channel.

By doing the above, the positions of the rectangular units within one block on the screen are far from each other, but between blocks between channels that are recorded simultaneously in parallel on the tape, the rectangular units that correspond to each other The units will also be adjacent to each other on the screen.

Therefore, the amount of information in each fixed-length block is less likely to be biased, so that the efficiency of variable-length encoding can be improved. Further, the point that maintaining the continuity of the positions on the screen between the fixed length blocks of the two channels will ensure the ease of viewing the screen during high-speed playback will be explained later.

An error correction code is added to the blocked data by an error correction encoder 16, and the data is digitally recorded on a magnetic tape 17. At this time, two recording heads 23 record two
Data corresponding to fixed length blocks (blocks identified by R and L) are simultaneously recorded in parallel.

During playback, two playback ends 24 are transferred from the magnetic tape 17.
are used to simultaneously detect digital signals in parallel, and an error corrector 18 corrects errors generated in the tape head system. Since the recording signal has been variable length coded, the code compressed by the variable length code decoder 19 is restored to its original state. The decoded signal is converted back into a digital video signal by the inverse orthogonal transformer 20. At this point, the signals have been rearranged in rectangular units, so the input/output addresses of the memory are controlled by the rearrangement memory 21 so that the data is rearranged in the opposite manner to that on the recording side. The rearranged signals are output by the defomatter 22 as reproduced digital signals in the same line order as the video signal.

Digital V with two channels simultaneous recording as in this example
In high-speed playback in TR, the two playback heads 24 of the rotary drum diagonally cross a plurality of trunks simultaneously as shown in FIG. 3, with respect to the trunks recorded on the tape. Here, blocks composed of adjacent rectangular units on the screen are recorded on two tracks (for example, R and L in the figure) that are simultaneously recorded by the two recording heads 23 during recording. Whenever the reproducing head 24 crosses two tracks (R and L), blocks consisting of adjacent rectangular units on the screen are simultaneously detected and reproduced. Therefore, according to this embodiment, even during high-speed playback, a wide screen area can be played back continuously, and mosaicing of the screen in units of rectangles can be avoided.

As described above, according to this embodiment, since the plurality of rectangular units included in one fixed-length block are located apart from each other on the screen, when the rectangular units are variable-length encoded, each fixed-length block The amount of information is less likely to be biased, and compression efficiency is improved. Furthermore, since adjacent rectangular units on the screen are always included between blocks on two tracks that are simultaneously recorded and played back in parallel, screen continuity can be ensured even during high-speed playback, making it visually A high-speed playback screen that is easy to view can be obtained.

In this embodiment, a configuration for simultaneous recording and reproduction of two channels is shown, but the greater the number of channels, the more effective the continuity of the screen during high-speed reproduction will be.

In addition, as shown in the block numbers for each customer rectangle in the screen division explanatory diagram in Fig. 2, even on the same channel, that is, on the same track on the tape, the screen This is even more effective because it increases the continuity of

Further, in this embodiment, orthogonal transformation is used as the compression means, but other methods may be used as long as the screen is encoded in units of rectangles. Also, the recording method is rotary head type digital VT.
Although R is used, it may be in the form of a disk.

As described in detail, according to the present invention, it is possible to achieve both the efficiency of high-efficiency encoding of a video signal and the image quality in high-speed reproduction from a recording medium, and its practical effects are significant.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a digital video signal recording and reproducing device according to an embodiment of the present invention, Fig. 2 is an explanatory diagram of screen division in the embodiment, and Fig. 3 is a tape pattern diagram during high-speed playback in the embodiment. , FIG. 4 is a screen diagram for explaining a rectangular unit, FIG. 5 is a block diagram of a conventional digital video signal recording and reproducing apparatus, and FIG. 6 is a diagram of a tape pattern in conventional high-speed reproduction. 11...Formatsuta, 12.21...
・Sort memory, 13...Orthogonal transformer, 14
...Variable length encoder, 15...Blocker, 16...Error correction encoder, 17...
...Magnetic tape, 18...Error corrector, 1
9...Variable length code decoder, 20...Inverse orthogonal transformer, 22...Deformator, 23.
... Recording head, 24 ... Playback head. Diagram

Claims (2)

[Claims] (1) a rearrangement means for rearranging the order of signals in rectangular units obtained by dividing a pixel set on a screen of a digital video signal into rectangles; a variable-length encoding means for variable-length encoding the signals in rectangular units; a blocking means for collecting a certain number of said rectangular units to form a block of a fixed length; and a recording means for simultaneously recording said blocked signals on a medium in parallel using a plurality of channels; The means is composed of a plurality of rectangular units located apart from each other on the screen in one block, but the rectangular units included in the plurality of blocks are simultaneously recorded in parallel on the plurality of channels of the recording means. A digital video signal recording device characterized in that the rearrangement means are rearranged so that they are adjacent to each other on a screen. (2) detecting means for detecting the digital signal simultaneously recorded in parallel on a medium by the apparatus according to claim 1; decoding means for decoding the variable length code in the blocked signal; rearrangement means for rearranging the order of the signals in the rectangular units, the rearrangement means for rearranging the rectangular units included in the plurality of blocks obtained from the plurality of channels simultaneously recorded in parallel so that the rectangular units are adjacent to each other on the screen. 1. A digital video signal reproducing device characterized in that one block is composed of rectangular units located at mutually distant positions on a screen.