H.264 video coding standard uses motion estimation with multiple block sizes to reduce block-matching errors for higher rate-distortion performance. But the more modes are used

the more computation is needed linearly with the number of allowed block sizes. So a fast block motion estimation algorithm named multilevel successive elimination with half-stopping (MSEHS) is provided in this paper. According to the analysis of statistical characteristics about the best modes

multilevel successive elimination algorithm is described to speed up the searching process for the larger block modes firstly

then using the middle results SAD (sum of absolute difference) and motion vector

a half-stopping principle is defined as a threshold to judge whether it is necessary to continue the motion estimation for the smaller block modes. MSEHS algorithm not only reserves the advantage of multiple block modes in motion estimation but also deletes the redundant computation in the searching process. Experimental results show that the proposed technique provides competitive performance compared with full search algorithm

that is

highly reduced computational complexity

very similar image quality and bitrate.