Image coding method and image encoder

Abstract

The invention provides an image coding method and an image encoder. The method comprises: a to-be-coded coding block is divided into M sub coding blocks; a first rate distortion cost value, corresponding to an inter-frame 2N*2N prediction mode, of the coding block is obtained and respective rate distortion cost values, corresponding to the inter-frame 2N*2N prediction mode, of the M sub coding blocks are obtained; according to the rate distortion cost values, corresponding to the inter-frame 2N*2N prediction mode, of the M sub coding blocks, a first estimation value, corresponding to a rate distortion cost value of an inter-frame 2N*N prediction mode, of the coding block as well as a second estimation value, corresponding to a rate distortion cost value of an inter-frame N*2N prediction mode, of the coding block is determined; on the basis of the first rate distortion cost value, the first estimation value, and the second estimation value, an optimal prediction mode of the coding block is determined; and according to the optimal prediction mode of the coding block, prediction coding is carried out on the coding block. Therefore, the coding complexity of the image is reduced.

Description

technical field [0001] The present invention relates to the field of image encoding and decoding, and more specifically, relates to an image encoding method and an image encoder. Background technique [0002] Compared with H.264 / AVC, the High Efficiency Video Coding (HEVC) standard protocol has obvious advantages. Under the same subjective experience, the HEVC code stream can be reduced by half. The HEVC coding architecture consists of modules such as intra prediction, inter prediction, rate distortion optimization (Rate Distortion Optimization, RDO), entropy coding, and loop filtering. [0003] Specifically, during encoding, the largest coding unit (Largest Coding Unit, LCU) is used as the unit, and the image block with the size of 64×64 is divided into four blocks with the size of 32×32 layer by layer according to the quadtree structure. 16 blocks of size 16×16 and 64 blocks of size 8×8. Each coding block in each layer needs to use multiple inter-frame prediction modes a...

AI Technical Summary

Problems solved by technology

[0010] As mentioned above, compared with H.264 / AVC, when encoding HEVC, not only the division of blocks becomes complicated, but the number of coding blocks increases, but also the number of intra-frame and inter-frame prediction modes supported by each coding block increases.

When encoding an image block, it is necessary to use all the inter-frame and intra-frame prediction modes corresponding to each coding block for prediction, and select the prediction mode with the smallest rate-distortion cost value as the optimal prediction mode for the coding block, resulting in Image coding complexity is high

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