基于熵编码CABAC的信源信道联合解码器

Joint Source Channel Decoder Based on CABAC

H.264的熵编码都采用基于上下文自适应二进制算术编码(CABAC),能达到较高的压缩性能,但对信道误码非常敏感.文中提出了一种基于CABAC的算数码变长码联合解码算法,联合信源信道算数码解码之后的信息作为变长码的输入信息,再通过变长码格状图搜索获得最佳的符号序列.同时,在算数码解码部分可以利用变长码的码字结构信息来删除无效搜索路径,提高解码性能.仿真实验表明,该联合迭代解码算法明显优于传统的分离解码器.

H.264 has been widely used in recently years.The entropy coding method used in H.264 is context-based adaptive binary arithmetic code（CABAC）.Although CABAC can achieve high compression,it is very sensitive to channel errors.In this paper,a novel joint arithmetic and variable length decoding algorithm based on CABAC was proposed.The transmitted sequence bits were first decoded by a joint source channel arithmetic decoder,the output of which was decoded by joint variable length decoder（JVLD）.The trellis graph was used to search the best symbol sequence.Furthermore,at the process of joint arithmetic decoding,the searching path was canceled if the decoded sequence did not conform to the vlc structure,thus achieving better decoding performance.Experimental result indicates that the proposed algorithm is superior to the separate scheme.