Fast Motion Estimation of H.264/AVC by Adaptive Early Termination

M.G. Sarwer, T.M. Nguyen, and Q.M.J. Wu (Canada)


H.264/AVC, rate-distortion (RD) cost, video coding, and motion estimation


H.264/AVC provides considerable performance improvement compared to previous video coding standards. To improve the performance, H.264/AVC uses variable block size motion estimation process. However, the motion vector (MV) estimation with different block size may require huge computing time. To reduce the complexity of motion estimation process, this paper proposed an early termination algorithm with adaptive threshold. The adaptive threshold is developed based on the statistical characteristics of rate-distortion (RD) cost of the current block with that of previously processed block and modes. The motion estimation process will be terminated as soon as the computed RD cost is below a threshold and threshold is adaptive and also depends on the RD cost of the previously calculated macroblocks (MBs) and modes. Thus, most of the motion searches can be stopped early and then a large number of search points can be saved. The experimental results show that the proposed method reduces about 68% and 24% motion estimation time of full search and fast motion estimation, respectively with ignorable degradation of the rate distortion performance.

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