Improved Adaptive Transform for Residue in H.264/AVC Lossless Video Coding
Xianfeng Ou, Guoyun Zhang, Guo Longyuan, Jianhui Wu, Bing Tu, Long Yang · Automatika · 2016
The H.264/AVC was designed mainly for lossy video coding, the lossless coding of H.264 use bypass mode for DCT and quantization. Although sample-by-sample DPCM improves performance of coding, the benět is limited in intra. In this paper, a new adaptive transform is proposed based on the character of 4×4 block residual coefčient’s distribution, which can be used both in intra and inter coding. The greatest strength of the proposed transform is the decorrelation without in ation versus dynamic range of input matrix. Due to the random distribution of residual coefčcients, a specič transform is hard to play a positive impact on them. Therefore, several transforms of different directions will be implemented simultaneously, and the most efčient one will be determined by a proposed mechanism. Then, by means of statistic method, a new scan order is designed for CAVLC entropy encoder, cooperating with corresponding transform. The simulation results show that based on the fast algorithm of proposed method, the bit saving achieves about 7.41% bit saving in intra coding and 10.47% in inter, compared with H.264-LS.