Optimization on motion estimation algorithm based on H. 264

Motion estimation is a very important part of video compression. As a result of using precision of motion vector in H.264 encoder, the computational cost increases rapidly, and motion estimation is the most time-consuming stage. In this paper, based on the UMHexagonS algorithm, an optimized algorithm is proposed based on the dynamic search window selection, big hexagon and small hexagon search mode respectively, which saves motion estimation time effectively with a little quality loss. Experiments with some typical video sequences show that compared to the original UMHexagonS algorithm, this new algorithm can save about 17.851% motion estimation time and reduce the complexity of original scheme as well as enhance the real time performance of encoder and almost has no changes in the reconstructed picture quality and bitrates.