基于SATD准则的HEVC快速帧内预测算法

摘要

相比于H.264/AVC视频编码标准,高效视频编码(HEVC)具有更大的压缩率和计算复杂度.HEVC更多的帧内预测模式显著地提升了编码器的率失真性能,但更高的算法复杂度使得编码时间大大增加.通过对典型序列编码的统计分析,提出一种基于变换残差绝对值和(SATD)的帧内预测模式快速选择算法,以降低HEVC帧内预测过程的计算复杂度.所提算法通过比较SATD来加速帧内预测模式的判决,避免了耗时的率失真代价(RD-Cost)计算,并且选择性地降低候选预测模式的数量,以减少总体编码时间.通过与现有其他HEVC快速算法进行比较测试,结果表明,所提算法平均减少了12.90%~19.89%的编码时间(编码器不进行任何优化),而BD-Rate码率指标仅增加了0.5%~0.96%,几种算法的率失真性能基本一致.%As compared with H.264/AVC, the High Efficiency Video Coding(HEVC)has greater compression ratio and computation complexity. The increase of HEVC intra prediction modes can improve its Rate-Distortion(RD) perfor-mance at the cost of greater encoding complexity, which leads to the significant increase of encoding time. According to the statistical analysis, this paper proposes a fast intra prediction algorithm based on the SATD(Sum of Absolute Trans-formed Differences)criterion for HEVC, which can selectively reduce the number of candidate modes and accelerate the mode decision by comparing the SATD to avoid unnecessary RD-Cost calculation. In contrast with other fast intra-mode decision algorithms in HEVC, the proposed algorithm averagely provides about 12.90%~19.89% speedup(without any platform or source code level optimization)with just the 0.5%~0.96%BD-rate(Bjontegaard Delta rate)increase accord-ing to the HEVC common test conditions, and significantly reduces the encoding time while maintaining a similar RD per-formance.