JPH052829A - Recording system for digital video signal - Google Patents

Abstract

PURPOSE:To reduce the degradation of the picture quality of a reproduced picture by recording a digital video signal in a recording disk by compressing data so that the smaller the radius of the recording track is, the larger N of data compression rate 1/N becomes. CONSTITUTION:A data compression encoded digital video signal reproduced from a disk 1 is supplied to a elongation decoding circuit 8 and a microcomputer 12 by a head 4. After a data elongation decoding is performed for the signal with a data elongation rate N in accordance with a data compression rate 1/N according to the track of the recording disk 1 in an elongation decoding circuit 8 under the control of the microcomputer 12, the signal is supplied to a D/A converter 9 and the D/A conversion is performed for it, and an analog video signal is obtained at an output terminal 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital video signal recording system.

[0002]

2. Description of the Related Art When a digital video signal is recorded on a recording disk, since the data amount is large, a digital video signal for one frame is recorded over several tracks, and an analog video signal is recorded. 1 compared to the case
The time that can be recorded on one recording disk is shortened.

Therefore, when recording one frame of a digital video signal on one track of a recording disk, the recording disk is rotated at a constant rotation speed to record the digital video signal. Since the recording track has a small amount of information that can be recorded, it is necessary to compress the digital video signal and record it. For this reason, in the past, assuming that the data compression rate required for recording a digital video signal on the innermost recording track of the recording data was 1 / n, the entire digital video signal would have this constant data compression rate. The data is compressed with 1 / n and then recorded on the recording disk.

[0004]

However, if the digital video signal is data-compressed and recorded on the recording disk, the quality deterioration of the reproduced image cannot be denied. In view of such a point, the present invention is intended to propose a recording method of a digital video signal in which deterioration in the quality of a reproduced image is reduced.

[0005]

DISCLOSURE OF THE INVENTION According to the present invention, recording of a digital video signal is carried out by compressing a digital video signal at a compression rate of 1 / N and recording it on a recording disk 2 rotating at a constant rotation speed. In the method, N is set to be larger as the radius of the recording track of the recording disk is smaller.

[0006]

Embodiments of the present invention will be described in detail below with reference to FIG. FIG. 1 shows a recording / reproducing apparatus for a digital video signal. Reference numeral 1 is a recording disk, that is, an optical disk, which is rotationally driven by a motor 3 via a rotary shaft 2 at a constant rotational speed.

Next, the recording system will be described. The analog video signal from the input terminal 5 is supplied to the A / D converter 6 to be converted into a digital video signal, which is then supplied to the compression encoding circuit 7 and under the control of the microcomputer 12, the data compression rate 1 / N (N is 1 or a value greater than 1 and is an integer, integer + fractional number or fraction, etc.) and then data compression coding is performed, and then the head (optical pickup) together with the data of the data compression rate.
4, and the recording laser light is converted into recording laser light for recording on the disk 1. The data of the data compression rate may be stored in the memory of the microcomputer 12 together with the track number.

The radius of the innermost track of the recording disk is set to 5
When the radius of the outermost track is set to 0 mm and one frame of the digital video signal is recorded on one track with the radius of the outermost track being 150 mm, for example, in the outermost track, the data compression rate 1 / N is set to 1/2, In the inner track, the data compression rate 1 / N is set to 1/6. Therefore, in this case, if the radius of the track is Rmm, the data compression rate 1 / N in that case is 1 / (2R / 50) = 25 / R. still,
All the tracks of the recording disk 2 are divided into a plurality of areas, and the data compression rate is made equal for the tracks in each area.
The data compression 1 / N, N, may be increased toward the inner area.

Next, the reproducing system will be described. The data compression coded digital video signal reproduced from the disk 1 by the head 4 is supplied to the decompression decoding circuit 8 and the microcomputer 12. Microcomputer 1
In accordance with the data compression rate 1 / N (separated from the reproduced digital video signal or read from the memory of the microcomputer 12) corresponding to the track of the recording disk 1 under the control of 2. After the data expansion and decoding with the data expansion rate N, the D / A converter 9
To D / A conversion, and an analog video signal is obtained at the output terminal 10.

As the compression encoding method described above, AD
CT (Adaptive Discrete CosineTransform), orthogonal transform, Hadamard transform, etc. can be used.

In the above embodiment, the case where the recording disk is an optical disk has been described, but it may be another disk such as a magnetic disk or a magneto-optical disk.

[0012]

According to the above-described digital video signal recording system of the present invention, the data compression rate of the digital video signal becomes 1 / N as the radius of the recording track becomes smaller on the recording disk.
Since the data is compressed so that N becomes larger, the data is recorded on the recording disk, so that the image quality of the reproduced image is less deteriorated.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

[Explanation of symbols]

 1 recording disk 3 motor 4 head (optical pickup) 6 A / D converter 7 compression encoding circuit 8 decompression decoding circuit 9 D / A converter 12 microcomputer

Claims (1)

Claim: What is claimed is: 1. A digital video signal recording method, wherein a digital video signal is data-compressed at a compression rate of 1 / N and recorded on a recording disk rotating at a constant rotation speed. A recording method of a digital video signal, wherein the N is set to be larger as the radius of the recording track of the disc is smaller.