【摘要】 在H.264/AVC中,帧内编码采用帧内预测来提高编码效率．色度块尺寸为8×8,亮度块包括4×4和16×16两种尺寸,每种块提供多种预测模式,因此这种多模式选择极大地增加了编码复杂性．本文利用色度块和亮度块以及亮度4×4和16×16块模式选择之间的相关性,提出一种基于RDO(Rate distortion optimization)不同判决依据的快速帧内预测模式选择算法,并能够自适应调整阈值．实验结果表明与校验模型JM7.2相比在信噪比和码率变化不大的同时,能够使I帧编码速度平均提高6倍,并可节约P帧25%的编码时间．更多还原

【Abstract】 In H.264/AVC,intra-prediction is used to improve the coding efficiency of I- frames.The size for the chroma block is 8×8,and the sizes for the luma block are 4×4 and 16×16.Each kind of block provides many prediction modes,so that this multi-mode selection increases the coding complexity greatly while improving coding efficiency.In this paper,a fast intra-prediction mode selection algorithm with adaptive thresholds and different criterion based on RDO(Rate Distortion Optimization)is proposed using the mode selection relation of chroma block and luma block and the relation of luma 4×4 block and luma 16×16 block.Experiment results show that the proposed algorithm can averagely speed up 6 times for I frame coding or provide 25% time savings for P frames in comparison with JM7.2 while maintaining similar PSNR and bit rate.更多还原