基于H．264的UMHexagonS算法研究

运动估计是视频压缩领域的关键技术。H．264编码器采用了高精度运动矢量，计算量迅速增长，运动估计消耗整个编码时间80％左右。在所提出的算法建立在分析UMHexagonS算法的基础上，在搜索窗口的大小选择，螺旋搜索及多层次六边形搜索的搜索点数减少3个方面进行了优化，保持了原有图象质量的同时有效地节省了运动估计时间。通过实验证明，优化后的算法与其他算法相比，在重建图象质量和码率接近的情况下，运动估计时间平均节省了12％，一定程度上提高了编码器的实时性。

Study on UMHexagonS Algorithm based on H.264

Motion estimation is a key technology in video compression field.H.264 Encoder,with the adoption of high-precision motion vector,has a rapid increase in computation complexity,and ME costs about 80% of the whole encoding time.The proposed algorithm,based on UMHexagonS algorithm,is optimized in such three aspects as the dynamic search range selection,full-search and big hexagon search mode,thus to save ME time effectively without quality loss.Experiment results show this algorithm can save about 12% of Me time as compared to UMHexagonS algorithm while enhance the real-time performance of the encoder without any decline of reconstructed picture quality and bitrate.