Method and apparatus for compressing and decompressing image

Abstract

The invention provides a video coding and decoding system, and a macro block compression / decompression method and a device thereof, belonging to the technical field of video coding and decoding, comprising the following steps: the maximum value and the minimum value of the pixel point lightness value inside a macro block are obtained; according to the maximum value and the minimum value of the pixel point lightness value inside the macro block, the quantization step distance of the pixel point lightness value and the quantization step value of the pixel point lightness value inside the macro block are calculated; the quantization step value of the pixel point lightness value inside the macro block closest to the lightness value of the pixel points in the macro block is searched in the quantization step value of the pixel point lightness value of the macro block; the found quantization step value closest to the pixel point lightness value inside the macro block is adopted as the pixel point lightness value in a compressed macro block, and an image index value is created for the pixel point lightness value inside the compressed macro block; a quantization index value table is created according to the maximum value and the minimum value of the pixel point lightness value inside the macro block and any two values in the quantization step distance.

Description

technical field [0001] The invention belongs to the technical field of video coding and decoding, and in particular relates to a video coding and decoding system and a method and a device for compressing / decompressing brightness values ​​of pixels inside a macroblock in an image. Background technique [0002] Existing video codec standards, such as H.264, H.263, XVID, RMVB, Moving Picture Experts Group (MPEG), etc., their codec processes are all in line with figure 1 Shown: In the decoding process, the previously decoded frame data must be used as the reference frame of the new decoded frame. The data stream generated during the decoding process - the residual value and the calculated macro block (Macro Block, MB) value are all online, that is, stored in the register of the video codec hardware device or the Synchronous Dynamic Random Access Memory (Synchronous Dynamic Random Access Memory) , SDRAM) and other on-chip memory. For large-capacity reference frames (I frame, P ...

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