The complexity of video encoders in the international standards of H.263

MPEG- 4

H.264

depends mainly on the block motion estimation algorithm.In order to make motion estimation algorithm faster and more accurate

a fast motion estimation algorithm based on probability matrix is proposed in the paper.In the algorithm

every possible motion vector's probability of current macro block is estimated by the previous macro blocks' motion vectors

and constitutes the probability matrix whose size is as the same as the search window's.The algorithm restricts the number of pixels to search by probability.From the results of experiment

comparing the proposed algorithm and diamond search algorithm

it shows that the veracity is improved a little

and the speed grown faster at the same time.