AVS是我国自主制定，拥有自主知识产权的音视频编码技术标准。AVS采用了可变大小块以及1／4像素精度的运动估计技术以提高编码效率。基于AVS参考软件提出了一种增强亚像素自适应范围搜索算法。该算法主要使用了小菱形窗的搜索策略和阈值判决方法。与亚像素全搜索算法比较，在平均性能仅下降0．0093dB的情况下，减少了30．25％的搜索点数。与AVS参考软件中的快速亚像素运动估计算法相比较，在平均性能提高0．0221dB的同时，节省了8．78％的搜索点数。

AVS is a new audio and video coding standard in China, in which variable block sizes and quarter-pel motion compensation have been applied to improve coding efficiency. In this paper, an adaptive range fractional pel search algorithm is proposed to further speed up the encoding process and reduce the computation complexity. Small diamond search and threshold judgment are used to this algorithm. Compared with the half-pel full search algorithm, experiments show that the proposed algorithm can reduce the sub-pel search points by 30. 25% on average with the limited performance lost about 0. 009 3dB. And compared with the fast search algorithm in AVS reference software, experiments show that the proposed algorithm can reduce the sub-pel search point by 8.78% on average with the performance achieve a gain up to 0. 0221dB.