Fast multi-frame motion estimation and mode decision for H.264 encoders

H.264/AVC achieves higher compression efficiency than previous video coding standards. However, this performance gain comes at the cost of an increased computational complexity due, in part. to the use of variable block size motion estimation, multiple reference frames, and rate-distortion mode decision. In this paper, we develop a combined algorithm for fast motion estimation and mode decision by exploiting the motion and cost information available from the blocks that have been processed prior to the current block. At the cost of a slight bit rate increase and PSNR drop, this method, on the average, is about 10.5 times faster than the H.264 reference software JM 8.5 in the total encoding time.