Hardware realization method for rapidly decoding CAVLC (context-adaptive variable-length coding) run_before code

A hardware implementation and codeword technology, applied in the field of digital video signal encoding and decoding, can solve the problem of time-consuming and achieve the effect of improving the decoding speed

Active Publication Date: 2014-08-06
FUDAN UNIV
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Problems solved by technology

[0009] For hardware decoding, calculating the magnitude of non-zero coefficients and the run_before codeword is the most time-consuming process in the entire CAVLC decoding process

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  • Hardware realization method for rapidly decoding CAVLC (context-adaptive variable-length coding) run_before code
  • Hardware realization method for rapidly decoding CAVLC (context-adaptive variable-length coding) run_before code
  • Hardware realization method for rapidly decoding CAVLC (context-adaptive variable-length coding) run_before code

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Embodiment Construction

[0023] The present invention will be further described below in conjunction with the accompanying drawings.

[0024] The specific implementation of the fast decoding run_before codeword of the present invention is as follows:

[0025] (1) Code table splitting and codeword merging.

[0026] The code table for decoding the run_before codeword specified in the H.264 video standard is shown in Table 1. Only one run_before codeword value can be obtained by querying this code table once. In order to speed up the decoding process, we split this code table into 7 code tables according to the value of zerosLeft. Table 2 is the code table for zerosLeft>6. Table 3 is the code table for zerosLeft=6. Table 4 is the code table for zerosLeft=5. Table 5 is the code table for zerosLeft=4. Table 6 is the code table for zerosLeft=3. Table 7 is the code table for zerosLeft=2. Table 8 is for the code table when zerosLeft=1. Among them, Table 3, Table 4, Table 5, Table 6, and Table 7 adopt...

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Abstract

The invention belongs to the field of digital video signal encoding and decoding technology, in particular to a hardware realization method for rapidly decoding CAVLC (context-adaptive variable-length coding) run_before code. Two methods of code table partition and code combination are used in the method, fourteen run_before codes with each having a value of 0 or two run_before codes not equal to 0 can be decoded at most in one clock period. The input video code stream firstly passes through a preamble 1 detector to detect whether run_before code to be decoded is zero, the preamble 1 detector can detect at most 14 bits of preamble 1 once. When the value of a current run_before code is not zero, if the total number of 0 included before the current decoding position is counted as zerosLeft, the run_before code can be sorted into seven types according to the value of zerosLeft, the run_before code table specified in the original standard is partitioned into seven sub-code tables, the code is decoded for each type. With the method, the data processing capability of the hardware decoder can be greatly increased.

Description

technical field [0001] The invention belongs to the technical field of digital video signal encoding and decoding, and in particular relates to a hardware implementation method for decoding a CAVLC run_before codeword. Background technique [0002] H.264 / AVC (Advanced Video Coding) is an international video coding standard jointly formulated by the International Telecommunications Organization (ITU) and the Moving Picture Experts Group (MPEG), and has been widely used in the field of multimedia audio and video. H.264 / AVC stipulates that its entropy coding can adopt two methods: Context Adaptive Variable Length Coding (CAVLC) and Context Adaptive Arithmetic Coding (CABAC). CABAC has higher encoding efficiency, but the complexity of encoding and decoding is also greatly increased, while CAVLC has a better balance between encoding efficiency and complexity. Compared with the previous generation of video standards such as MPEG-1 and MPEG-2, the coding efficiency of CAVLC has be...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04N19/13H04N19/44H04N19/156H04N19/42
Inventor 范益波沈沙沈蔚炜曾晓洋
Owner FUDAN UNIV
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