New Lookup Tables and Searching Algorithms for Fast H.264/AVC CAVLC Decoding
Jun-Young Lee, Jae‐Jin Lee, Seongmo Park · IEEE Transactions on Circuits and Systems for Video Technology · 2010
In this paper, new codeword structures, tables, and searching methods for fast and efficientcoeff_token,total_zeros, andrun_beforedecoding are developed. This new achievement is mainly based on the fact that the context-adaptive variable length coding (CAVLC) decoding can be modeled as a finite state machine. In order to quantitatively evaluate the proposed method in terms of decoding speed and complexity, we define the iteration bound$\left({{1}\over {\mathtilde{\tau}}}\right)$and thecomplexity ratio$(CR)$. Using these gauge variables, we show that the new algorithms reduce${\mathtilde {\tau}}$to about one third andcomplexity ratioto 0.95. This means that the proposed techniques reduce the decoding time to about one third and memory access count by 90% compared to those of the conventional methods without implementation overheads. Multiple-symbol parallel decoding method forrun_beforesyntax element is proposed based on abit-positioningwith the critical path latency of only one multiplexer for the post-combination process. The proposed methods make it possible to implement a fast and efficient CAVLC decoding without losing video quality on any environments.