Yang Yang, Stanković Vladimir, Xiong Zixiang, Zhao Wei
Dept. of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843, USA.
IEEE Trans Image Process. 2009 Mar;18(3):534-51. doi: 10.1109/TIP.2008.2010148.
Following recent works on the rate region of the quadratic Gaussian two-terminal source coding problem and limit-approaching code designs, this paper examines multiterminal source coding of two correlated, i.e., stereo, video sequences to save the sum rate over independent coding of both sequences. Two multiterminal video coding schemes are proposed. In the first scheme, the left sequence of the stereo pair is coded by H.264/AVC and used at the joint decoder to facilitate Wyner-Ziv coding of the right video sequence. The first I-frame of the right sequence is successively coded by H.264/AVC Intracoding and Wyner-Ziv coding. An efficient stereo matching algorithm based on loopy belief propagation is then adopted at the decoder to produce pixel-level disparity maps between the corresponding frames of the two decoded video sequences on the fly. Based on the disparity maps, side information for both motion vectors and motion-compensated residual frames of the right sequence are generated at the decoder before Wyner-Ziv encoding. In the second scheme, source splitting is employed on top of classic and Wyner-Ziv coding for compression of both I-frames to allow flexible rate allocation between the two sequences. Experiments with both schemes on stereo video sequences using H.264/AVC, LDPC codes for Slepian-Wolf coding of the motion vectors, and scalar quantization in conjunction with LDPC codes for Wyner-Ziv coding of the residual coefficients give a slightly lower sum rate than separate H.264/AVC coding of both sequences at the same video quality.
继近期关于二次高斯双终端源编码问题的速率区域及接近极限的码设计的研究工作之后，本文研究了两个相关的（即立体的）视频序列的多终端源编码，以节省相对于对两个序列进行独立编码的总速率。提出了两种多终端视频编码方案。在第一种方案中，立体视频对的左序列由H.264/AVC编码，并在联合解码器处使用，以促进右视频序列的Wyner-Ziv编码。右序列的第一个I帧依次通过H.264/AVC帧内编码和Wyner-Ziv编码进行编码。然后在解码器处采用基于循环置信传播的高效立体匹配算法，实时生成两个解码视频序列相应帧之间的像素级视差图。基于视差图，在Wyner-Ziv编码之前，在解码器处生成右序列的运动向量和运动补偿残差帧的边信息。在第二种方案中，在经典编码和Wyner-Ziv编码之上采用源分割来压缩两个I帧，以允许在两个序列之间灵活分配速率。使用H.264/AVC对立体视频序列进行这两种方案的实验、使用LDPC码对运动向量进行Slepian-Wolf编码以及结合LDPC码对标量量化进行残差系数的Wyner-Ziv编码，在相同视频质量下，总速率比两个序列单独进行H.264/AVC编码略低。
