High-Speed CAVLC Encoder for 1080p 60-Hz H.264 Codec

摘要

In H.264/AVC and the variants, the coding of context-based adaptive variable length codes (CAVLC) requires demanding operations, particularly at high bitrates such as 100 Mbps. This letter presents two approaches to accelerate the coding operation substantially. Firstly, in the architectural aspect, we propose component-level parallelism and pipeline techniques capable of processing high-bitrate video data in a macroblock (MB)-level pipelined codec architecture. The second approach focuses on a specific part of the coding process, i.e., the residual block coding, in which the coefficient levels are coded without using look-up tables so we minimize the pertaining logic depth in the critical path, and we achieve higher operating clock frequencies. Additionally, two coefficient levels are processed in parallel by exploiting a look-ahead technique. The resulting architecture, merged in the MB-level pipelined codec system, is capable of coding up to 100 Mbps bitstreams in real-time, thus accommodating the real-time encoding of 1080p@60 Hz video.