JPH03213090A - Moving picture encoding system for storage - Google Patents

Abstract

PURPOSE:To suppress reduction in the quality of a reproduced picture by preparing plural encoding forms corresponding to the respective resolutions of a luminance signal and a color difference signal, selecting one encoding form corresponding to the kind of source picture data and executing the data compression of the both signals with the corresponding resolution. CONSTITUTION:The frequencies for respective clock conversion circuits 21, 31 and 41 to take out the luminance signal are successively set higher corresponding to the resolution of the luminance signal with corresponding encoding forms 11, 13 and 15. The frequencies for the respective clock conversion circuits 21, 31 and 41 to take out the color difference signal are successively set lower corresponding to the resolution of the color difference signal with the corresponding encoding forms 11, 13 and 15. At encoder parts 20, 30 and 40, filters 22, 33 and 43 are arranged on the input sides of the clock conversion circuits 21, 31 and 41 and for picture element values to be taken out by the clock conversion circuits 21, 31 and 41, a smooth processing is executed according to the preceding and following picture element values. Then, the source picture data are thinned out. Thus, the reduction in the quality of the picture can be suppressed.

Description

[Detailed Description of the Invention] [Summary] Regarding a coding method used in a video storage device that records and plays back video images, the purpose of this invention is to reduce deterioration in the quality of reproduced images, and to improve the quality of luminance signals and color differences. In a storage video encoding method that encodes original image data decomposed into signals at a predetermined resolution and compresses them into corresponding luminance signal data and color difference signal data, multiple The apparatus is configured to include an encoding means that prepares encoding formats, selects one encoding format according to the type of original image data, and compresses the luminance signal and color difference signal at the corresponding resolution.

[Industrial application field]

The present invention relates to an encoding method used in a moving image storage device that records and plays back moving images.

[Conventional technology]

The moving image storage device captures moving images one screen at a time, and records the luminance signal (Y) and color difference signal (C,...) for each pixel.
C,), and the original image data converted into digital signals is encoded and stored.

Here, since image information has a large amount of information and requires time to transfer, data compression is required to store image information.

One method of data compression is to set a resolution for each of a luminance signal and two color difference signals, and thin out data from the original image data at predetermined intervals depending on the resolution. This method takes advantage of the fact that human vision is less sensitive to color differences than brightness, and increases the thinning rate of color difference signals as shown in Figure 5 (a), et al., and (C). The degree of compression is further increased.

[Problems to be Solved by the Invention] In the conventional encoding method, the above-mentioned resolution is fixed and arbitrary moving images are encoded at the same resolution.

For this reason, depending on the type of moving image, the quality of the reproduced image may deteriorate. For example, in a moving image containing a mixture of multiple colors, the thinned out color data may be uneven depending on the resolution of the color difference signal, and only the same color may be extracted from the original image data and compressed. In some cases, the reproduced image became extremely difficult to see.

The present invention is intended to solve these problems,
It is an object of the present invention to provide a storage video encoding method that can reduce deterioration in the quality of reproduced images.

[Means to solve the problem]

FIG. 1 is a block diagram of the principle of the present invention.

In the figure, in the storage video encoding method, original image data decomposed into luminance signals and chrominance signals are encoded at predetermined resolutions, and compressed into corresponding luminance signal data and chrominance signal data.

In the present invention, a plurality of encoding formats 11.13.15 are prepared corresponding to each resolution of the luminance signal and the color difference signal, and one of the encoding formats is selected according to the type of original image data.
Encoding means 17 is provided for data compressing the luminance signal and color difference signal at corresponding resolutions.

[For production]

In the method of the present invention, a plurality of encoding formats IL13.15 corresponding to each resolution of the luminance signal and color difference signal are prepared, and one of them is selected according to the type of original image data for encoding. It is possible to reduce the deterioration of the quality of the product. For example, for a moving image with many color changes, a clear reproduced image can be obtained by selecting and encoding an encoding format in which the resolution of the color difference signal is high and the resolution of the luminance signal is low.

[Example] The detailed operation of the example will be described below based on the drawings.

The video storage device that adopts the method of the present invention supports the resolution of luminance signals and color difference signals where the amount of information in the encoded output for one screen (the sum of the information amounts in the encoded outputs of the luminance signal and color difference signal) is the same. A plurality of encoding formats are set in advance. In this embodiment, three encoding formats 11.13,
Set I5.

In encoding format 11, the resolutions of the luminance signal and the two color difference signals are set to be the same.

Encoding format 13.15 increases the resolution of the luminance signal in order from the resolution of the luminance signal set in encoding format 11,
Correspondingly, the resolution of the color difference signal is gradually lowered.

Encoding format 11 is suitable, for example, for storing moving images with many color changes within the screen, and encoding format 15 is suitable, for example, for storing moving images with few color changes within the screen. Format 13 is for storing moving images that fall between the types of moving images to which encoding format 11.15 is applied.

FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention.

Hereinafter, an embodiment will be described in detail with reference to FIG.

In the figure, one screen of a moving image is decomposed into a luminance signal and two color difference signals for each pixel, and each is converted into a digital signal to become original image data as shown in FIG. The original image data is input to three encoding units 20, 30, and 40.

The encoding unit 20.30.40 includes a clock conversion circuit 21.3 that outputs the original image data in the encoding format 11.13.15.
1.41, extracts data from each of the luminance signal and color difference signal of the original image data at a frequency corresponding to each resolution, compresses the data, and outputs the encoded data.

Here, the frequency at which each clock conversion circuit 2, 31.41 extracts the luminance signal is determined by the corresponding encoding format 11.13.
．． The resolutions of the 15 luminance signals are set higher in order. Further, the frequency at which each of the clock conversion circuits 21, 31, and 41 extracts the color difference signal is set lower in order according to the resolution of the color difference signal of the corresponding encoding format 11 and 3.15.

In addition, in the encoding section 20.30.40, a filter 23.33.4 is connected to the input side of the clock conversion circuit 21.31.41.
3 is installed, and the clock conversion circuit 21, 31, 41 performs smoothing processing on the pixel value extracted by the pixel values before and after it,
An attempt is made to reduce the deterioration in image quality due to thinning out the original image data.

The order of the smoothing process in the filter 23.33.43 is determined according to the operation of the clock conversion circuit 21.31.41. For example, as shown in FIG. 4, each pixel value on the same horizontal line of the original image data...Z, -2, Zn-
1. When the clock conversion circuit 21 extracts data at three intervals from Zn% Zn+l, Zn+2'', the corresponding filter 23 performs the following smoothing process on the pixel value Zi at the extraction position n. .

In this way, the encoding units 20, 30, and 40 perform encoding processing in parallel, and each output is input to the selector 50.

A control signal is input to the selector 50, and the outputs of the encoding units 20, 30, and 40 are selected and output according to the control signal.

The control signal is a signal input manually by an operator who monitors the moving image displayed on the display device. When accumulating moving images to be displayed, the operator determines the type of moving image, such as whether the moving image has many color changes,
Specifies one of the three encoding formats described above. This designation becomes a control signal input to the selector 50.

In other words, the original image data is encoded with a resolution that corresponds to the type of moving image.

The output of the selector 50 is stored with a control code indicating the encoding format added to the beginning.

At the time of reading, the encoding format is determined from the control code added to the beginning, and reproduction is performed according to the encoding format.

〔Effect of the invention〕

According to the present invention, a plurality of encoding formats corresponding to each resolution of the luminance signal and chrominance signal are prepared in advance, one of them is selected according to the type of original image data, and the luminance signal and chrominance signal are encoded. do.

Therefore, the resolution of the luminance signal or color difference signal can be increased depending on the type of moving image, and it is possible to reduce the deterioration in image quality when the encoded data is reproduced.

[Brief explanation of drawings]

Figure 1 is a block diagram of the principle of the present invention, Figure 2 is a block diagram showing the configuration of an embodiment, Figure 3 is a diagram explaining original image data, Figure 4 is a diagram explaining the operation of the filter, and Figure 5 is a diagram explaining the operation of the filter. FIG. 2 is a diagram illustrating a conventional encoding format. In the figure, 11.13.15 is the encoding format, 17 is the encoding means, 20.30.40 is the encoding unit, 2131.41 is the clock conversion circuit, 23.33.43 is the filter, and 50 is the selector. . Types of original image dataPrinciple block diagram of the present inventionFigure 2 Diagram explaining the original image dataFigure 2 Diagram explaining the operation of the filter

Claims (1)

[Claims] (1) Luminance signal (Y) and color difference signal (C_1, C_2
) is encoded at a predetermined resolution and compressed into corresponding luminance signal data and chrominance signal data, which corresponds to each resolution of the luminance signal and the chrominance signal. A code that prepares a plurality of encoding formats (11, 13, 15), selects one encoding format according to the type of the original image data, and compresses the luminance signal and the color difference signal at a corresponding resolution. 1. An encoding method for storing moving images, characterized in that it comprises a converting means (17).