中文摘要：

为了降低H．264的计算复杂度以满足实时应用，在对H．264帧内编码模式深入研究的基础上，提出利用宏块灰度直方图特征在Intra4×4和Intral6×16模式中预判，针对Intra4×4模式采用基于子块预测方向特征的快速帧内预测算法．综合以上2种优化策略，该优化算法平均码率增加了3．2％，峰值信噪比基本不变的情况下，编码速度平均提高了32．8％．

英文摘要：

To reduce the encoding time for H. 264 and apply it to the real-time practice, on the basis of the research on the block size prediction of intra frame and according to the histogram algorithm, an intra 4 × 4 mode or intra 16 × 16 mode for every macro-block are selected before coding. If the intra 4 × 4 prediction mode is chosen, then the fast algorithm based on the characteristic of macro-block itself is used to reduce the choices for predicted directions. Experimental results show that without the variety of PSNR, the compression time is 32.8% less than that of the original and it increases 3.2% bits rate.