A lossless approach for external memory bandwidth reduction in video coding systems and its VLSI architecture

This paper presents the Reference Frame Context Adaptive Variable-Length Coder (RFCAVLC), which is a lossless solution to external memory bandwidth reduction in current video coding systems. The proposed approach is based on an adaptation of the traditional Huffman algorithm, and it uses eight static tables to avoid the cost of the on-the-fly statistical analysis. The best table to encode a block is defined using a context evaluation, resulting in a context-adaptive configuration. The use of RFCAVLC reached an average compression rate higher than 31% for the evaluated video sequences. The architectures that implement the RFCAVLC encoder and decoder were designed and synthesized to an FPGA device. The RFCAVLC design is able to reach real-time encoding for WQSXGA (3200 × 2048 pixels) at 30 fps. The synthesis results show that this solution can be easily coupled to a complete video encoder system with negligible hardware overhead and without compromising the throughput for real-time high-definition multimedia applications.