中文摘要：

针对高度优化的x264模式判断算法进行了研究，准确定位了其中仍存的冗余点．在此基础上，基于层次化思想，对模式判断流程进行了重新组织，提出了帧间辅助模式失效条件、帧间主要模式有效条件以及相应的模式选择算法．实验表明，所提算法在几乎不损失压缩质量的前提下使编码速度得到了显著提升．此外，该算法不仅适用于P帧，而且适用于B帧，能够全面提升x264编码器的编码速度．

英文摘要：

This paper carries out research on the highly optimized mode decision algorithm of x264 software and accurately pins out its redundant points. The mode selection process is reorganized hierarchically. Auxiliary inter modes＇ invalidating condition and main inter modes＇ validating condition are proposed. New mode selection algorithm based on them is designed. According to the experimental results, the new algorithm brings remarkable speed gain for both P and B slices.