Motion estimation (ME) consumes most of the computational resource in a video encoder system. H.264 adopts multimode ME and quarter pel accuracy fractional pixel search

which brings about large scale of computational cost not only to integer pixel ME but also to fractional pixel ME. However

the computational cost of integer pixel ME has been greatly reduced with the development of fast integer search algorithms. Therefore

fast fractional pixel ME algorithms become significantly important for real time applications. A novel fractional pixel motion estimation based on prediction of flat regions of an image is first proposed in this paper. It reduces fractional pel search points efficiently by predicting flat homogeneous regions of the image. Experimental results show that compared to the full fractional pixel search

the proposed method can reduce 22% to 63% of fractional pixel search points while keeping the image quality and compression rate almost unchanged.