Early termination for TZSearch in HEVC Motion Estimation

The TZSearch algorithm was adopted in the high efficiency video coding reference software HM as a fast Motion Estimation (ME) algorithm for its excellent performance in reducing ME time and maintaining a comparable Rate Distortion (RD) performance. However, the multiple initial search point decision and the hybrid block matching search contribute a relatively high computational complexity to TZSearch. In this paper, based on the statistical analysis of the probability of median predictor to be selected as the final best point in the large Coding Units (CUs) (64×64, 32×32) and small CUs (16×16, 8×8) as well as the center-biased characteristic of the final best search point in ME process, we propose two early terminations for TZSearch. Experimental results show that the proposed early terminations can achieve 38.96% encoding time saving, while the RD performance degradation is quite acceptable.