A High-performance Hardwired CABAC Decoder for Ultra-high Resolution Video.

Context-Based Binary Arithmetic Coding (CABAC) is one of two entropy coders used in H.264/AVC, which achieves a high compression ratio at the expense of high computational complexity. For real-time decoding of ultra-high resolution video, we propose a high-throughput hardwired CABAC decoder subsystem. By analyzing the distribution of different types of syntax elements (SE), we propose a Two-Bin arithmetic decoding engine (Two-Bin AE) to generate two bins in one cycle for the most frequent SEs. In order to boost the utilization of the proposed engine, we employ a Prediction-Based Parallel Processing Method to perform decoding and context index calculation in parallel. Furthermore, we propose a Context Table Reallocation Scheme, which can shorten the critical path delay of a Two- Bin AE circuit by 18%. Experimental results show that our decoder on average takes only 118 clock cycles to decode one macroblock (MB) at Main Profile, Level 4.0. For QFHD, i.e., 4×1080 HD, sequences, it can run effectively at 110MHz. The design has been successfully integrated into an H.264/AVC QFHD video decoder in an SOC system. [ABSTRACT FROM AUTHOR]