Fast CAVLD of H.264/AVC on bitstream decoding processor

This paper presents a fast context-based adaptive variable-length decoding (CAVLD) method of H.264/AVC with a very long instruction word-based bitstream processing unit (BsPU) designed for entropy decoding of multiple video formats. A new table mapping algorithm for the coeff_token, level, and run_before syntax elements of the quantized transform coefficients is proposed, and many branch operations are removed by utilizing several designated instructions in the BsPU. By applying designated instructions and the proposed table mapping algorithm to CAVLD, we found that the proposed fast CAVLD method achieves an increase of approximately 47% in the decoding speed and a reduction of approximately 59% in memory requirements for the table mapping.