Abstract: Intra prediction is a key technique of improving H.264 encoding efficient，but its computational complexity is the bottleneck of intra-encoding.After a simple analysis of the intra prediction，a new fast algorithm is proposed，which is based on estimating the image texture direction.In the algorithm，the block texture direction is estimated based on the adjacent pixels firstly，and then according to this direction the prediction mode is decided.The number of prediction modes and the algorithm complexity are reduced effectively.The experiment results show that the proposed algorithm can improve the H.264 encoding speed greatly with little image quality degradation and code-rate rise.

Key words: H.264 standard, intra prediction, texture direction, mode decision

摘要： 帧内预测是H.264取得高编码效率的关键技术之一，但其计算复杂度是H.264帧内编码中的瓶颈问题。结合H.264帧内预测特点，提出一种基于纹理估计的帧内预测快速算法。首先通过计算相邻宏块的边界像素差值，估计图像的纹理方向，再根据此方向选择相应的帧内预测模式，减小候选模式数量，简化模式选择过程，降低了帧内预测的计算复杂度。实验结果表明，在保证图像质量和编码码率的前提下，本算法能有效提高H.264的编码速度，有利于实时应用。

关键词: H.264标准, 帧内预测, 纹理方向, 模式选择