H.264/AVC帧内预测模式选择算法研究

Research of H.264/AVC intra-prediction mode selection algorithm

H.264/AVC采用空间域上的帧内预测技术,进一步提高了编码效率,但由于H.264/AVC支持的帧内预测模式数较多,使预测的复杂度大幅度增加。详细分析了帧内预测模式的选择过程,提出一种快速的率失真优化(RDO)模式下的快速Intra_4×4模式选择算法,该算法根据SATD(SumofAbsoluteTransformedDifference)以及相邻块的预测模式之间的相关性等特征,预先排除了超过65%可能性小的Intra_4×4模式,避免了不必要的计算,从而大幅度降低帧内预测的复杂度,同时基本保持了H.264/AVC的编码性能。

H.264/AVC employed intra-prediction technique in space domain to enhance coding efficiency, but it increased prediction complexity drastically because of quite a few intra-prediction modes. A new Intra_44 mode selection algorithm based on rate distortion optimization(RDO) was proposed. It employed SATD(Sum of Absolute Transform Difference) of each block as a judgment and used correlation between prediction modes of adjacent blocks to filter out more than 65% less probable modes beforehand so as to avoid unnecessary computations. The new algorithm reduces the intra-prediction complexity greatly while maintaining coding performance very well.