Optimized H.264 motion estimation algorithm based on UMHexagonS

H.264 has adopted UMHexagonS algorithm as fast motion estimation algorithm for integer pixel formally, but this algorithm has some shortages such as search points are lots, quantity of operation is kind of big, costs much time, and so on. These need to be solved as soon as possible. This paper introduces and analyses UMHexagonS algorithm. In order to solve these problems, this paper brings forward classification strategy for search algorithm according to statistical properties of the motion vector prediction value, and improves the template based on original algorithm according to the characteristic of center bias of motion vector. The results of experiments show that the improved algorithm in this paper reduces the time of motion estimation by 15%~27%. At the meantime, it can ensure PSNR and rate basically unchanged.