H.264引入帧内预测技术提高了I帧的编码效率，但也大大增加了编码的计算复杂度。为了降低计算复杂度，根据预测模式算法的特征提出了一种基于像素边缘矢量方差及子块宏块映射关系的帧内预测模式快速选择算法。实验结果表明，该算法在保证图像质量和比特率大致不变的前提下，极大地降低了帧内预测编码的计算复杂度。

H.264 introduces intraprediction coding technique to improve the intracoding efficiency.This enormously increases the computational complexity. In order to decrease the computational complexity of the algorithm, a fast algorithm for intra prediction mode decision based on pixel’s edge vector’s variance, the relation between subblock’s mode and macro block’s mode. Experimental results show that compared with the original intra prediction coding scheme, the proposed algorithm reduce the computational complexity of intra prediction coding dramatically with only trivial loss of PSNR and increment of bite rate.