CAVLC decoding method and system

Abstract

The invention discloses a CAVLC decoding method and a system. The method completes decoding of two successive Level syntactic elements in one clock period through the following processes: finding out the prefix length and the prefix code of the (2n-1)th Level syntactic element by using a lookup table used for syntactic element Level, acquiring an amplitude code of the (2n-1)th Level syntactic element by using the prefix code, the suffix code and the suffix length of the (2n-1)th Level syntactic element, and acquiring a coefficient amplitude corresponding to the (2n-1)th Level syntactic element according to the amplitude code of the (2n-1) Level syntactic element; and finding out the code initial position of the (2n)th Level syntactic element by using the prefix length and the actual suffix length of the (2n-1)th Level syntactic element, finding out the prefix length and the prefix code of the (2n)th Level syntactic element by using the lookup table used for the syntactic element Level, acquiring an amplitude code of the (2n)th Level syntactic element according to the prefix code, the suffix code and the suffix length of the (2n)th Level syntactic element, and acquiring a coefficient amplitude corresponding to the (2n)th Level syntactic element according to the amplitude code of the (2n)th Level syntactic element.

Description

technical field [0001] The present invention relates to the field of video processing, more specifically to a CAVLC decoding method and system. Background technique [0002] CAVLC (Context Adaptive Variable Length Coding) is an entropy coding technique for reducing bit rate and making full use of statistical redundancy, and is widely used in video standards such as H.264. During the CAVLC encoding process, the encoding process of the following five syntax elements is usually involved: Coeff_token, Trailing_ones_sign (referred to as T1 for simplicity), Levels, Total_zeros, and Run_before. The corresponding relationship between these five syntax elements and the relevant statistical information of the chrominance / luminance coefficient block as the coding object is as follows: [0003] [0004] In the CAVLC decoding process, the dependencies between symbols in the input bit stream and the unknown code length of each codeword before the codeword is decoded have a great impac...

AI Technical Summary

Problems solved by technology

This method can effectively improve the decoding speed of the run_before syntax element when there are few or no zero-value coefficients in the entire coefficient block; but when the quantization parameter (QP) increases, that is, when the number of zero-value coefficients increases, The speedup effect of this algorithm is reduced; and for the chroma DC (direct current coefficient) block, the method is not efficient

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