在H．264视频编码过程中，编码时间受诸多因素的影响，如帧间／帧内模式选择、运动估计（ME）、率失真优化（RDO）等。为了以较快速度和较好质量进行编码，针对H．264帧内模式选择，提出了一种适用于H．264帧内4×4块预测的模式选择快速算法。该算法利用帧内4×4块最优预测模式与和它相邻的预测模式之间率失真代价（RDCost）的高相关性，以及绝对变换误差和（SATD）与率失真（RD）性能之间的强相关性，有效地跳过一些不太可能的预测模式，从而使帧内4×4块模式选择过程只需进行4次率失真代价计算即可。实验结果显示，该算法在编码性能和编码速度之间取得了很好的折衷。

In the video-encoding process, the encoding time is greatly influenced by many factors, such as inter/intra mode decision, motion estimation(ME), etc. In order to encode the videowith faster speed and beteer quality, this paper only focuses on the intra mode decision in H.264 and presents a fast intra prediction mode decision algorithm for 4×4 blocks in H.264. The proposed algorithm uses: (i) high correlation of RD cost between best prediction mode and its neighborhood prediction mode, (ii) strong correlation between sums of absolute transform differences(SATD) and rate-distortion(RD) performance, efficiently skipping some unlikely prediction modes. Thus, it can complete 4×4 intra prediction by only computing RD cost for four times. The simulation result shows that the proposed algorithm is a good compromise between the coding performance and the encoding speed.