An improved EPZS(enhanced predictive zonal search) algorithm with direction based search patterns and adaptive motion estimation scheme selection based on prediction block type is presented in this paper. Utilizing high special/temporal correlation of motions in video sequences and focusing on the interactions between motion estimation and new coding tools such as multiple references and prediction block types

the algorithm can obtain almost the same PSNR as full search at very low computation cost. Compared with EPZS

it can considerably improve the speed of motion estimation

and rate distortion performance. Experiments verify the superiority of the proposed algorithm. Furthermore

the proposed algorithm is robust and capable of generating a smooth motion vector field.