Optimized CABAC decoder

Abstract

A device employing techniques to optimize Context-based Adaptive Binary Arithmetic Coding (CABAC) for the H.264 video decoding is provided. The device includes a processing circuit operative to implement a set of instructions to decode multiple bins simultaneously and renormalize an offset register and a range register after the multiple bins are decoded. The range register and offset registers may be 32 or 64 bits. The use of a larger range register allows renormalization to be skipped when enough bits are still in the range register.

Description

technical field This disclosure relates generally to the field of video decoding, and more specifically, to techniques for optimizing context-based adaptive binary arithmetic coding (CABAC) for H.264 video decoding. Background technique To support the H.264 main specification, context-based adaptive binary arithmetic coding (CABAC) is a technical challenge. The basic concept of binary arithmetic decoding processing is recursive interval division. The arithmetic decoding engine core maintains two registers. The first register is a range register with 9 bits. The second register is an offset register that is 9 bits in normal mode and 10 bits in bypass mode. The range register keeps track of the width of the current interval. The offset is from the bitstream and points to the current position within the range. When decoding a bin, the range is divided into two subintervals depending on the context in which that particular bin is decoded. After the bin is determined, the r...

AI Technical Summary

Problems solved by technology

Thus, there are numerous bitwise operations in the CABAC core, frequent renormalization, and bitwise reads from the bitstream, all of which are computationally cumbersome.

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