Fast approaches for sub-pixel precision variable block size motion estimation

The new features of H.264 video coding standard make the motion estimation module much more time consuming than before. Especially, the motion search is required for each of the 4 modes for inter prediction. In order to reduce the computational complexity, we analyze the statistics of results of motion estimation, such as the continuity of best modes of blocks in successive frames and the chance to give up a sub-partition mode (smaller than 16×16) after integer-pixel motion estimation, from which we suggest to make mode prediction based on the motion information of the previous frame and skip sub-pixel motion estimation in sub-partition mode selectively. According to the experimental result, the proposed algorithm can save 75% of the computational time with a slight degradation (0.03 dB) on PSNR compared with the pseudocode of fast search motion estimation in JM12.2. Copyright Protection.