一种基于无比率LDPC编码的分布式视频压缩机制

摘要

针对固定码率LDPC码进行视频压缩时存在自适应能力差的问题,提出了一种基于无比率LDPC编码的Wyner-Ziv视频压缩机制.算法的主要思想是对部分变量节点调整删余比率以达到码率自适应的目的.同时采用一种新的在编码端进行码率估计的方法,克服了当前分布式编码码率调整需要反馈通道的问题,并为无比率LDPC编码设计多种编码模式提供了保障.实验结果表明,相对于LDPCA编码,提出的编码机制提升了系统率失真性能大约1-2dB,相对Motion-oracle算法解码复杂度要低2个数量级.%To overcome the poor adaptive ability of the fixed-rate Low-Density Parity-Check (LDPC) codes when applied to video compression, a kind of distributed video compression scheme based on rateless LDPC is proposed. The main idea of the algorithm is that part of variable node is punctured to adjust the puncturing ratio for rate adaptive ability. A novel rate estimation method is also proposed in encoder, it can solve the problem of needing the feedback channel for rate control in distributed video coding currently,and supply the rateless LDPC to design multiple code mode.Experiments results show that proposed scheme access the 1-2dB gain of rate distortion (RD) compared with rate-adaptive LDPC Accumulate (LDPCA) codes. The decoder complexity magnitude of proposed scheme is 2 orders less than the motion-oracle algorithm.