H.264帧内预测快速模式选择

H.264/AVC视频编码标准中用率失真优化(RDO)方法为一个宏块(MB)判决最佳编码模式来提高编码效果,加大了算法复杂度并且计算冗余大。为了克服这一缺点,一种快速帧内预测模式选择算法被提出。在色度预测中,根据宏块的色度纹理复杂度,把原先的4种模式降到1或2种;在亮度16×16块模式判决中,根据最小哈达玛变换的绝对误差和(SATD)来选择最佳模式;在亮度4×4块模式判决中,该算法在9种模式中选择3种可能模式作为候选模式。通过比较16个4×4块总代价与1个16×16块的代价来选择最佳块选择模式,实验表明,该算法能在节省69%左右编码时间的情况下,比特率与峰值信噪比(PSNR)保持不变。

Fast intra mode decision for H.264/AVC encoding

H.264/AVC uses the rate distortion optimization method to determine the best mode for a macroblock(MB)to improve coding efficiency.But it increases computational complexity.To overcome this shortcoming,a fast intra mode decision algorithm for H.264 is raised.In chroma prediction,four prediction modes can be reduced into one or two modes according to the textural features of a MB.In luma 16×16 prediction,the mode which has lowest Sum of Absolute Transformed Difference(SATD)can be selected as the best prediction mode.In luma 4×4 prediction,the algorithm chooses three probable modes from nine modes as the candidate modes.Comparing the total cost of sixteen 4×4 blocks and one 16×16 block,the best block size can be determined.Experimental results show that the coding time of the propose method is decrease about 68% while maintaining similar PSNR and bit rate performance of H.264 intra encoding.