JPS6059890A - Video signal recording and reproducing method - Google Patents

Abstract

PURPOSE:To prevent a reproduced color from being changed and deterioration of picture quality from being increased by encoding a luminance signal and a chrominance signal using two kinds of color difference signals in pairs to correctable codes to constitute a luminance code and a chrominance code. CONSTITUTION:A digitized luminance signal Y is applied to a terminal 1 and inputted to a coding circuit 9 via a frame memory 2. On the other hand, color difference signals I, Q are applied to terminals 4, 5, the signals I, Q are rearranged by a mixing circuit 6 and inputted to a coding circuit 10 as a signal C via a frame memory 7. The circuits 9 and 10 add respectively an error correction code to the signal Y read out of the memory 2 and the signal C read out of the memory 7 to obtain the luminance code Y and the chrominance code C. Then, a changeover circuit 11 changes over the codes Y and C by one frame each sequentially, the result is converted into a recording code at a modulation circuit 12, send to a recording/reproducing section 13 and recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention separates a television signal converted into a digital signal or a still image signal similar to a television signal into a luminance signal and a color signal, and transmits the signal to a magnetic disk or optical disk. The present invention relates to a method for configuring an error correction code and a method for recording and reproducing video signals related to a recording format when recording on a recording medium.

Conventional Structure and Problems Conventionally, in recording video signals, analog recording has been used in which analog signals are modulated and recorded.

In recent years, with the remarkable development of digital signal processing technology,
Digital recording, which converts video signals into digital signals and records them, has been introduced.

In particular, in broadcasting systems and the like, it is desirable to record video signals in the form of component signals, since various digital signal processings cannot be performed on the video signals. Component signals used in broadcasting systems, etc. include Y, which represents brightness.
There are color difference signals representing signals and color signals, engineering signals and Q signals, or (RY) signals and (B-Y) signals. Hereinafter, the explanation will be made using the ■ signal and the Q signal as the color difference signals.

Recording media that can be randomly accessed include magnetic disks for magnetically recording and reproducing, and optical disks for optically recording and reproducing. When recording digital signals on such recording media, it is inevitable that some errors will occur. Therefore, error correction codes are used to correct the errors that have occurred. For example, optical disks currently have a higher error rate and more burst errors than magnetic disks. Therefore, it is impossible to correct all errors using error correction codes. In this case, errors are detected from the correctly reproduced signal, and correction is performed by interpolating the error portions.

For example, a line in which an error has occurred is replaced with a signal from one line before.

A conventional example in which this modification is applied to a color difference signal, an optical signal, and a Q signal will be explained.

As shown in Figure 1, in an image where the upper half of the screen is red and the lower half is blue, the value of the ■ signal is large in the upper half, and the value of the Q signal is large in the lower half. ing. If an uncorrectable error occurs in the engineering signal on the 1st line of the boundary of the blue part, the 1H previous line (K
-1) Replace with line adjustment engineering signal. The next line to be repaired is ■Signal,
Both Q signals are large and appear purple on the playback screen.

In this way, when a color signal is modified using a portion with a small correlation, it may be reproduced as a different color, significantly emphasizing image quality deterioration. Therefore, when recording component signals on a recording medium such as an optical disk, it is necessary to have an error correction code configuration, saturation, and recording format that do not increase the deterioration of the image quality of the reproduced screen.

Purpose of the Invention The present invention has been made in view of the above points, and an object of the present invention is to increase the deterioration of the image quality of the playback screen even if an error occurs when recording a component signal on a recording medium. The purpose of the present invention is to provide a configuration, modification, and recording format of an error correction code that will not cause problems, and to provide a recording format that can shorten the search time when searching for images recorded on a disk.

Structure of the Invention In the present invention, component signals (Y signal, ■ signal, Q signal
Among the signals), the ■ signal and the Q signal are combined into one set and constitute an error correction code as a color signal (hereinafter referred to as a C signal).

When an uncorrectable error occurs, even if only one of the (2) signal and the Q signal is in error, both signals are corrected. However, the correction can prevent the reproduced colors from being changed and image quality deterioration from increasing.

Further, the Y signal constitutes an error correction code only with the Y signal.

Regarding the Y signal and the C signal, if at least one of the signals is correctly reproduced, the deterioration in image quality will be smaller than if both signals are erroneously reproduced at the same portion. Therefore, even if a burst error occurs, in order to prevent the error portions of the Y signal and the C signal from overlapping on the screen, the locations where the two signals are recorded are separated on the recording medium.

If an optical disc is used as a recording medium, it is currently possible to record approximately 1000 images on one disc using digital component signals. Therefore, when selecting a desired image, it is necessary to search while sequentially playing back the images.

At this time, if a complete image is reproduced one by one, the search time will be long.

However, when searching, it is only necessary to know the content of the image, so Y
In many cases, just reproducing the signal is sufficient.

In the present invention, as described above, since the Y signal and C signal recording areas of one frame are recorded separately, reproduction of only the Y signal can be easily realized.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail using screens. FIG. 2 is a block diagram showing the configuration of a recording section of a video signal recording and reproducing apparatus using the recording method according to the present invention. In FIG. 2, the digitized component signal F)Y'fij- is applied to the input terminal 1.

The memory controller 3
) and the write control signal Wσ) are sent to the frame memory 2. The frame memory 2 writes the Y signal for one frame period.

Add the ■ signal and the Q signal of the digitalized combo net signals to the input terminals 4 and 5, respectively.The mixing circuit 6 rearranges the 1 signal and the Q signal and sends it out as the C signal. - The roller 8 receives the atl female signal Ad(
C) and write control signal W(C) to the room memory 7. The frame memory 7 stores one C signal for one frame period.

As described above, one frame of video signal is separated into a Y signal and a C signal, and stored in the frame memory 2 and the frame memory 2, respectively.

The encoding circuit 9 adds an error correction code to the Yi code read from the frame memory 2 and sends it out as a Y code. The encoding circuit 10 adds an error correction code to the C signal read from the frame memory 7 and sends it out as a C code. The switching circuit 11 sequentially switches the Y code and the C code one frame at a time and sends out the signals. The modulation circuit 12 is supplied from the switching circuit 11 and is supplied with CY? Convert the ``+Kano'' and ``C'' codes into ``E'' recording codes suitable for the recording medium, and send them to the recording/reproducing section 13. The recording/reproducing unit 13 records the recording code on a recording medium such as an optical disc.
＼I completely depend on myself.

In the 31st page, the configuration of the playback section of the video signal recording and playback device, which takes into account the recording methods mentioned in each of the inventions, is shown at 20 degrees in a navel diagram. 3 to 7'
1: Sends the Y code to the correction circuit 16 and the C code to the correction circuit 18, respectively, according to the class J■, V1.

The correction [[j1 path 16 uses an error correction code to detect and correct the portion where an error has occurred, and sends the corrected Y signal to the frame 2 mebiliary 20. The memory control 21 is
Address signal Ad(Y), write control signal W(
Send Y), F■/-ノ, to memory 20, endogenous! 7. Write the Y signal for one frame.

When the correction circuit 16 detects an incapable of correction error,
An uncorrectable signal is sent to the correction circuit 17.

When the correction circuit 17 receives the uncorrectable signal, the correction circuit 17 outputs a correction signal corresponding to the line in which the uncorrectable error has occurred.
- Delivered to roller 21.

When the memory controller 21 receives the modification signal, the address signal Ad(Y) to be sent to the frame memory 20 is set to 1.
Change to the address signal before the line and send. The frame memo IJ20 replaces the signal of the line where the uncorrectable error has occurred with the signal of the previous line and reads it out 7, and outputs it to the output terminal 2.
Send from 5.

Regarding the C signal, the correcting circuit 1B, the correcting circuit 19, the frame memory 22, and the memory controller 23 transmit the reproduced C signal to the arene memory 2 in the same manner as the Y signal.
The separation circuit 24 separates the C signal read from the frame memory 22 into an engineering signal and a C signal, and sends them out from output terminals 26 and 27, respectively.

FIG. 4 shows an example of the recording format 1 when an optical disk is used as the recording medium in the embodiment shown in 1-1 below. The Y signal and C signal of the th frame are
If expressed as Y(K) and C(K), respectively, the Y signal and C signal of each frame are recorded concentrically as shown in FIG. For example, if the trunk pitch is 1.5 μm,
If each signal of one frame is recorded on 20 tracks, the Y signal and C signal of the same pixel will be recorded on 30 tracks on the optical disk.
Since recording will be performed at a distance of μm, the probability that errors will occur at the same time becomes extremely small.

Furthermore, when searching for recorded images, the search time can be halved by jumping the recorded portion of the C signal and reproducing only the Y signal.

-Also, even if the transfer 1/-1- from the TV is slow, the 71/-memory 20 and the frame memory 22 shown in Fig. 3 can be read out and monitored even in the middle of playback according to the 1υ of the TV broadcast. In the recording format shown in Figure 4, the display is sequentially played back starting from the Y signal, so a black-and-white screen is played back in 10% of the time, reducing the psychological burden of waiting time. Become.

In the recording format shown in FIG. 4, each signal is recorded in units of one frame, but it is also possible to divide this into units of fields and record them.

This can be realized by switching the Y signal and the C signal using the switching circuit 11 shown in FIG. 2 every time one field is read from the frame memory. In this case, if the display screen at the time of search is field playback, the search time can be significantly shortened.

Generally, in broadcasting systems and the like, the following ratios of sampling frequencies for component signals are often used.

Y:I:Q=2:1:1 The number of quantization bits per sample is the same for each sample, ranging from 8 bits to 10 bits.

Therefore, if the configuration of the error correction code is divided into the Y signal and the C signal (■signal 10 signal) as in the present invention, the number of bits per code length will be the same for both signals, and the error correction code will be added. The encoding circuit that performs error correction and the correction circuit that performs error correction
It can be made common to the signal and the C signal.

As described in detail, according to the present invention, when recording component signals, a correction code is constructed by combining the ■ signal and the C signal as one set, and even when an uncorrectable error occurs, correction is performed as one set. Therefore, it is possible to prevent the reproduction color from being changed and image quality deterioration to increase due to retouching.

By separating the recording locations of the Y signal and the C signal on the recording medium, it is possible to prevent the error portions of the Y signal and the C signal from overlapping on the playback screen and to significantly deteriorate the image quality.

At the time of search, the search time can be halved by reproducing only the recorded portion of the Y signal.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a monitor screen, FIG. 2 is a block diagram showing the configuration of a recording section of a video signal recording and reproducing apparatus using a recording and reproducing method according to an embodiment of the present invention, and FIG. FIG. 4 is a block diagram showing the configuration of a reproducing section of a video signal recording and reproducing apparatus using the recording and reproducing method in one embodiment. FIG. 4 is a schematic diagram showing a recording format on a disc. 2.7, 20, 22... Frame memory, 3゜8.21.23... Memory controller, 9,
10... Encoding circuit, 13... Recording and reproducing section, 16.18... Correction circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure/ 2 (/ Figure 3

Claims (2)

[Claims] (1) When recording a video signal expressed as a component signal of a luminance signal and two types of color difference signals, the two types of color difference signals are encoded as a set of color signals to enable error detection and correction. The color code and the brightness code are recorded at separate recording locations on a recording medium. Video signal recording and playback method. (2) Continuously recording the luminance code of one frame or one field for a video signal of one frame period or one field period, and then continuously recording the color code of the frame or field. A video signal recording and reproducing method according to claim 1, characterized in that: