Abstract: This paper proposes a new fast adaptive motion estimation algorithm based on H.264.It uses the statistics of video sequence and the correlation of SADs in the space to early terminate the search，and it determines the search pattern according to the block’s motion activity，proposes a new unsymmetrical synthetic diamond search pattern.Compared to Fast-Full-Search，the PSNR is just 0.017 dB lower and bitrates is 0.45% high while the speed is 15 times up.With same image quality to algorithm in JM，the speed is 35% faster.

Key words: adaptive, motion estimation, block matching algorithm

摘要： 提出了一种基于H.264的快速自适应运动估计算法。利用视频序列的统计特性和SAD在空间上的相关性提前结束搜索；根据块的运动量来确定搜索方式；提出了一种新的非对称综合的菱形搜索模式，与快速全搜索算法相比较，该算法的峰值信噪比只下降了0.017 dB，码率只上升了0.45%，而搜索速度提高了15倍；与H.264参考程序中的运动估计算法相比，在图像质量相同的情况下，搜索速度提高了35%。

关键词: 自适应, 运动估计, 块匹配算法