JPH02220270A - Digital video signal recording and preproducing device - Google Patents

Abstract

PURPOSE:To obtain a video to look at easily at the time of high speed reproducing by devising an extended change of a digital video signal, putting plural rectangular units in a fixedly long block in apart positions from one another on a screen, making a coding high efficient and making the rectangular units contained in adjacent blocks on a recording medium correspondingly adjacent even on the screen. CONSTITUTION:At the time of recording, the screen is divided into areas A-F and the rectangular units A1, B1...,A2, B2... by a formatter 11, and one unit by unit is taken out of each area in turn to be rear-ranged and stored in a memory 12. A signal of each rectangular unit is coded by a orthogonal converter 13, and the data capacity is reduced in accordance with the size of information quantity in the rectangular unit by a variable length encoder 14. As a result, imbalance of the information quantity is hardly generated among individual fixedly long blocks, and the variably long coding efficiency is promoted, and then the continuity of data on the screen between the adjacent fixedly long blocks is maintained, thus ensuring the easiness to look at the screen at the time of high speed reproducing. A correction code is added by an error correction coder 16 to the block formed data to be recorded on a tape 17. At the time of reproducing, high speed reproducing screen is obtained in approximately reverse order.

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 compression).

FIG. 4 shows a block diagram of this conventional digital video signal recording and reproducing apparatus, where l 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 manually inputted to the first error correction encoder l, an error correction code is added, and the digital video 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 error correction again 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, eliminating the need for unnatural cuts 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 a fixed number of rectangular units to form a fixed length block.

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 the 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 reduction in efficiency. This has the problem that the efficiency of encoding does 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 present invention provides: (1) a sorting means for rearranging the order of signals in rectangular units in which a pixel set on a screen of a digital video signal is divided into rectangles; and a variable length code for converting the signals in rectangular units. a variable-length encoding means for collecting a fixed number of a plurality of rectangular units to form a fixed-length block; and a recording means for recording the blocked signal on a medium; is composed of multiple rectangular units located far apart on the screen within one block, and corresponding rectangular units included in adjacent blocks on the recording medium are also adjacent to each other on the screen. (2) detection means for detecting digital signals recorded on a medium by the apparatus according to item 1;
A decoding means for decoding the variable length code in the blocked signal, and a rearranging means for rearranging the order of the decoded signals in units of rectangles, the rearrangement means for decoding the variable length code in the blocked signal, and the rearrangement means Corresponding rectangular units included in each block are arranged so that they are adjacent to each other on the screen, and each block is composed of a plurality of rectangular units located far apart from each other on the screen. This is a digital video signal reproducing device characterized in that it is a replacement means.

Effect of the Invention The present invention employs the above-described configuration to rearrange digital video signals so that multiple rectangular units within a fixed-length block are positioned apart from each other on the screen to ensure high efficiency encoding. In addition, the corresponding rectangular units included in adjacent blocks in the form of a recording medium are arranged in adjacent positions on the screen, so that the screen does not become mosaic and is easy to see even during high-speed playback of a digital VTR. can.

Examples Examples of the present invention will be described below with reference to the drawings.

FIG. 1 shows a block diagram of a digital video signal recording and reproducing apparatus according to 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 records the encoded data on magnetic tape. In FIG. 1, 11 is a formatter, 12 is a sorting memo 1c, 13 is an orthogonal transformer, 14 is a variable length encoder, 15 is a block generator, 16 is an error correction encoder, 17
18 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 sorting memory, 2
2 is a defomatsuta.

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

During recording, the digital video signal is formatted by the formatter 11, and the pixel data is formatted in rectangular units on the screen.
The sorting memory 12 is manually inputted.

FIG. 2 is a diagram showing the dimensions of the rectangular unit on screen-E, and the entire rectangle represents one screen. In this example, the second
As shown in the figure, the screen is divided into six areas, A,
We will call them B, C, D, E, and F. Each area is further divided into rectangular units, and the rectangular units within each area are sequentially numbered as AI, A2, A3, and so on. In the sorting memory 12, the video signals are sorted in rectangular units as AI, Bl, CI, D.
I, El, Fl, A2. B2゜C2,
B2. F2. Sort them so that they are taken out one by one from each area, such as F2 fist...

The video signal in each rectangular unit is input to the orthogonal transformer 13, where it is orthogonally transformed encoded using a 7-Damar transform or cosine transform method, and then in the variable length encoder 14, the information amount in each rectangular unit is It is variable-length encoded according to the In variable length coding, orthogonal transformation is a means for achieving high efficiency coding by determining the amount of data depending on the amount of information in rectangular units and reducing the overall amount of data. 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 example, AI, Bl, CI, DI, El, F
One fixed length block is made up of six rectangular units of l, and A2
．． B2. C2, B2. F2. A method is adopted in which one fixed-length block is formed by the six rectangular units of F2.

By doing so, the positions of the respective rectangular units within one block on the screen are far from each other, but the mutually corresponding rectangular units of adjacent blocks are 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. In addition, by maintaining data continuity on the screen between adjacent fixed-length blocks,
Ensuring screen visibility 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.

During playback, digital signals are detected from the magnetic tape, and errors occurring in the tape head system are corrected by the error corrector 18. Since the recording signal has been variable length encoded, the compressed code is restored by the variable length code decoder 19. At this time, since one fixed length block is composed of six rectangular units, frame synchronization can be achieved in units of this block. 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 rearrangement memory 21 controls the human output address of the memory 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.

During high-speed playback on a digital VTR, the head moves across a plurality of tracks on the magnetic tape, as shown in FIG. Since data is continuously recorded in blocks on each track, signals can be captured continuously to some extent even during high-speed playback. In this embodiment, two corresponding rectangular units included in two consecutive blocks are located at consecutive positions on the screen, so a certain degree of screen continuity can be achieved even during high-speed playback, and the rectangular units can be Screen mosaic 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, two mutually corresponding rectangular units included in two adjacent blocks on the recording medium are:
Since they are adjacent to each other on the screen, continuity of the screen can be ensured during high-speed playback of a digital VTR, and a visually easy-to-read high-speed playback screen can be obtained.

Although orthogonal transformation is used as the compression means in this embodiment, other methods may be used as long as the screen is encoded in units of rectangles. Further, although a rotary head type digital VTR was used as a recording method, a disk type one may also be used.

DETAILED DESCRIPTION OF THE INVENTION As described in detail, according to the present invention, it is possible to achieve both the efficiency of high-efficiency encoding of video signals 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 apparatus according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of screen division in the embodiment, FIG. 3 is a front view for explaining rectangular units, and FIG. FIG. 4 is a block diagram of a conventional digital video signal recording and reproducing apparatus, and FIG. 5 is a tape pattern diagram for high-speed reproduction. DESCRIPTION OF SYMBOLS 1... First error correction encoder, 2... Shuffling memory, 3... Second error correction encoder, 4... Magnetic tape, 5... Second error corrector, 6 ...Deshuffling memo 1c 7. First error corrector, 11.. Formatter, 12.. Sorting memory, 13.. Orthogonal transformer, 14.. Variable length encoder , 15...Blocker, 16...Error correction encoder, 17...Magnetic tape, 18...Error corrector, 19...Variable length code decoder, 20...Inverse orthogonal Converter, 21... Sorting memory, 22... Default Matsuta.

Claims (2)

[Claims] (1) 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, a variable-length encoding means for variable-length encoding a signal in rectangular units, and a plurality of The rearranging means includes a blocking means for collecting a fixed number of rectangular units to form a block of a fixed length, and a recording means for recording the blocked signal on a medium, and the rearranging means is arranged such that the rearranging means mutually arranges the screens within one block. The recording medium is composed of a plurality of rectangular units located at separate positions on the recording medium, and the rectangular units corresponding to each other included in adjacent blocks on the recording medium are rearranged so that they are adjacent to each other on the screen. Digital video signal recording device. (2) a detection means for detecting a digital signal recorded on a medium by the apparatus according to claim 1; a decoding means for decoding the variable length code in the blocked signal; a rearrangement means for rearranging the order of the signals, the rearrangement means being configured such that corresponding rectangular units included in adjacent blocks on the recording medium are adjacent to each other on the screen; 1. A digital video signal reproducing device characterized in that within one block, the rearranging means is composed of a plurality of rectangular units located apart from each other on the screen.