用于H．264／AVC帧间预测的搜索算法

H．264／AVC标准编码过程中多步搜索（multi-step search method，MSSM）搜索点数多、占用的搜索资源大，而钻石搜索法（DSM，diamond search method）虽然占用的搜索资源少，其在预测准确性却有些欠缺．在此提出了改进的多步搜索算法（MSSM＋）．MSSM＋是在MSSM的基础上改进的，将其第1步搜索步长减半作为自己的第1步搜索步长，通过中心点匹配逐步减半搜索步长，直至搜索步长为1，并找到最终的匹配块．仿真结果表明，MSSM＋在预测准确性方面接近MSSM，而在搜索点数方面却有显著降低，提高了搜索效率，相对于DSM算法，在增加不多的搜索点数情况下取得了良好的预测准确性．

Search algorithm for H.264/AVC inter frame prediction

Aiming at the problems existed in the process of the coding under H.264/AVC standard, multi-step search method （MSSM） occupies a large number of search resources and leads to considerable search points, while the accuracy of diamond search method （DSM） occupies less search resources, but the relatively is low. This article proposes an improved multi-step search method （MSSM＋）. The MSSM＋ is improved on the basis of MSSM, in which its first search step is halved as its own first search step, gradually the search step is halved through the center point match until the search step is one, and finally the matching block is found. Simulation results show that the predictive accuracy of MSSM＋ is close to MSSM, while the points of search are significantly reduced, which significantly improves search efficiency, and MSSM＋ obtains favorable predictive accuracy by increasing a few number of search points compared with DSM.