One-round renormalization based 2-bin/cycle H.264/AVC CABAC encoder

摘要

Context-based Adaptive Binary Arithmetic Coder (CABAC) is the advanced entropy coding tool employed by main and higher profiles of H.264/AVC. As compared with Context-based Adaptive Variable Length Coding (CAVLC), under the same bit rate, CABAC achieves up to 0.5dB PSNR gain. On the other hand, the high complexity of CABAC severely hinders the whole encoder throughput. To overcome the throughput bottleneck of CABAC, the authors devise the one-round renormalization and the associated VLSI architecture to omit the multiple-iteration operation of one bin''s encoding. The proposed full-context CABAC hardwired encoder garners the constant 2-bin/cycle throughput. Using TSMC one-poly nine-metal 90nm CMOS technology, the prototyping is implemented with 33.9k logic gates and 1562-bit on-chip SRAM. In the worst operating conditions (0.9V, 125^°C), the operating frequency is 238.1MHz, which can support HDTV720p real-time encoding at 329fps frame rate with the quantization parameter (QP) not less than 18.