Intra mode prediction method and device and coder

Abstract

The invention discloses an intra mode prediction method, an intra mode prediction device and a coder. The method comprises the following steps of: when the optimal mode of an adjacent left block is a horizontal mode, taking the horizontal mode as the most possible mode of a block to be coded; when the optimal mode of an adjacent upper block is a vertical mode, taking the vertical mode as the mostpossible mode of the block to be coded; when the optimal modes of the adjacent left block and the adjacent upper block are the same, taking the same mode as the most possible mode of the block to be coded; when the serial numbers of the optimal modes of the adjacent left block and the adjacent upper block belong to a set {8, 6}, taking the horizontal mode as the most possible mode of the block tobe coded, and when the mode serial numbers of the optimal modes of the adjacent left block and the adjacent upper block belong to a set {3, 4} or {7, 5}, taking the vertical mode as the most possiblemode of the block to be coded; and selecting the optimal mode in the optimal modes of the adjacent left block and the adjacent upper block, which has a smaller mode serial number, as the most possible mode of the block to be coded. The embodiment of the invention can improve the accuracy of intra mode prediction.

Description

technical field [0001] The present invention relates to encoding technology, in particular to an intra-frame mode prediction method and device, and an encoder. Background technique [0002] In the intra-frame prediction of the video coding H.264 standard, the intra-frame mode of the block to be coded can be predicted in advance through the intra-frame mode prediction technology, and the predicted intra-frame mode is called the most probable mode. When the most probable mode is different from the optimal mode obtained by calculation, a total of 4 bits of encoding mode information need to be transmitted to the decoder in the code stream, where 1 bit indicates whether the most probable mode is the same as the optimal mode. , 3 bits represent the mode number of the optimal mode. When the most probable mode is the same as the optimal mode obtained by calculation, only one bit of flag information needs to be transmitted to the decoder in the code stream. The mode difference is r...

AI Technical Summary

Problems solved by technology

[0009] In the process of realizing the present invention, the inventors found that the existing intra-frame mode prediction technology has at least the following problems: According to the two adjacent blocks of the block to be encoded, namely: the optimal mode of the adjacent upper block and the adjacent left block When calculating the most probable mode of the block to be encoded, the mode corresponding to the smaller mode number among the optimal modes of the two adjacent blocks is used as the most probable mode of the block to be encoded. This method is more intuitive and relatively Simple, but ignores the relationship between the mutual position of the block to be encoded and the adjacent block and the mode direction, making the mode prediction of the current block to be encoded inaccurate, requiring more codewords to transmit mode information

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