Abstract: Motion estimation is a most times-consuming module in H.264 encoder. Early terminating motion search is a best method for improving motion estimation. In H.264 encoder, rate control computes the predicted SAD which can be used as a decision condition for terminating motion search. It can be proved that image quality has no changes if the difference between predicted SAD and best SAD is small. Experimental results show the proposed early terminating motion search can effectively improve motion estimation speed and keep good image quality.

Key words: integer transform, motion estimation, early terminating, predicted SAD, rate control

摘要： 根据H.264中整数变换、量化的特点，可以证明在宏块预测SAD和实际SAD的误差小于某一门限时，对编码质量不会产生影响。结合H.264码率控制算法中自适应SAD的预测，提出一种根据SAD预测值来提前终止运动搜索的快速运动估计方法。实验结果表明，该算法在图像质量稍有变化的情况下，能有效提高运动估计速度，最高可提高到2.2倍。

关键词: 整数变换, 运动估计, 提前终止, 预测SAD, 码率控制

CLC Number: 

• TP391