Joint optimization coding for level and map information in H.264/AVC

Since the joint optimization coding for the level and the map information of transformed coefficients has been applied to the image coding successfully, this paper addresses the problem of how to optimize the two parts of information of residual coefficients jointly in the state-of-the-art video coding standard - H.264/AVC. In order to solve this problem, this paper presents a pruning method to zero out residual coefficients, which are not valuable for encoding in rate-distortion optimization (RDO) sense. Furthermore, a joint optimization scheme is presented to combine scalar quantization with this pruning method together to further improve the compression performance of the proposed algorithm. Experiments have been conducted based on the reference encoder JM12.4 of H.264/AVC. Comparative studies show that the proposed joint coding method can achieve a PSNR gain more than 0.5 dB at a certain bit rate, compared with the coding method in the H.264/AVC. Especially, the PSNR gain can reach up to 0.9 dB, or equivalently, 17% bit rate saving can be achieved at some special cases.