Abstract: H.264 adopts Rate Distortion Optimization(RDO) to enhance coding efficiency at the cost of a very high computational complexity, and it is difficult to be real-timely implemented. By analyzing the factors of the computational complexity of the intra-frame mode selection, a fast algorithm for the intra-frame mode selection is proposed. After computing the SATDs of several modes with strong directivity, then finding out the correlation between the two smallest SATDs to choose, a new mode and expand it to the prediction range. Experimental results show that the total coding time reduces about 25%, and the coding time of I-frame reduces about 62% without obvious PSNR change.

Key words: H.264, intra-prediction, rate distortion optimization, mode selection

摘要： H.264使用率失真优化提高了编码的效率，但也增加了计算复杂度，不利于编码的实时实现。该文分析了H.264中计算复杂度较高的帧内预测模式选择部分，提出一种快速的帧内预测模式选择算法。对方向性较强的几种模式进行SATD计算，分析其中较小的两个模式的相关性来选择新的模式添加到模式选择的计算范围中，从而减少了预测模式的数量。实验结果证明，在图像性能和码率基本保持不变的情况下，总的编码时间下降了约25％，I帧的编码时间下降了约62％，满足了实时视频通信的要求。

关键词: H.264标准, 帧内预测, 率失真优化, 模式选择

CLC Number: 

• TN919.81