Memory bandwidth reduction for H.264 and HEVC encoders using lossless reference frame coding

This paper presents a hardware-efficient algorithm for external memory bandwidth reduction focusing on the state-of-the-art video encoders, like H.264/AVC and HEVC. The proposed approach is a lossless solution based on an adaptation of the traditional Huffman algorithm. This solution is entitled RFCAVLC8T (Reference Frame Context Adaptive Variable-Length Coder with 8 Tables) and is based on the use of off-line defined static Huffman tables. The RFCAVLC8T is a hardware-efficient version of the Huffman algorithm that employs eight static tables to avoid the cost of the on-the-fly Huffman statistical analysis. The best table to encode a block is selected at run time using a context evaluation, resulting in a context-adaptive configuration. The use of RFCAVLC8T reaches an average compression rate higher than 35% for the evaluated video sequences, with computational cost of a single VLC.