一种新的多假设运动补偿预测算法  

A New Multi-hypothesis Motion-compensated Prediction Algorithm

作　　者：黄为[1] 陈维荣[1] 

机构地区：[1]西南交通大学电气工程学院,成都610031

出　　处：《中国图象图形学报》2008年第3期428-434,共7页Journal of Image and Graphics

摘　　要：多假设运动补偿预测(multi-hypothesis motion compensated prediction,MHMCP)算法目前只应用于H.264/AVC视频编码标准中B帧的双向预测模式,因为其需对多个运动矢量及参考帧信息进行编码,而且其最终预测信号由前/后向参考帧中的最佳运动补偿信号(假设值)求和取平均值获得,精确性不够。针对MHMCP传统算法的缺陷,提出了一种新的MHMCP算法,即在保持当前最佳编码模式不变的基础上,首先通过加入前/后向运动矢量导出搜索模式来进行假设值的局部优化,并对多假设值进行自适应权重系数调整;最后通过比较率失真代价来选择最佳编码模式。模拟实验表明,该新算法可有效降低残差信号能量,不但能提高运动补偿预测信号的精确度,而且能使编码器获得更佳的率失真性能。Multi-hypothesis motion compensated prediction has been used as bi-directional prediction mode in B picture of the H. 264/AVC video compression standard. The optimal motion-compensated prediction signal, named hypotheses, is composed of blocks in both forward and backward reference pictures,which are simply added and averaged to synthesize the final prediction signal. In the original algorithm, more than one motion vector and reference information has to be encoded and the accuracy of motion-compensated prediction is still insufficient. To overcome these disadvantages, a new rate-distortion optimization based MHMCP algorithm is proposed. After the optimal MB＇s encoding mode has been obtained by motion estimation and mode decision procedure,bi-directional motion search with iterative local motion vector refinements will be started. At the same time, two extra mv-tracking modes which need not to encode additional side information will be examined, accompany with adaptive hypothesis-coefficients adjustment. Experimental results show that not only the energy of the residual signal can be decreased but also the quality of the motion-compensated prediction signal can be improved. Therefore better R-D performance can be achieved by the proposed algorithm.

关 键 词：多假设运动补偿预测 率失真优化 H.264/AVC 运动估计 

分 类 号：TP919.81[自动化与计算机技术]