Distributed video coding for wireless video sensor networks: a review of the state-of-the-art architectures <s> DVC architectures <s> In current interframe video compression systems, the encoder performs predictive coding to exploit the similarities of successive frames. The Wyner-Ziv theorem on source coding with side information available only at the decoder suggests that an asymmetric video codec, where individual frames are encoded separately, but decoded conditionally (given temporally adjacent frames) could achieve similar efficiency. We report the first results on a Wyner-Ziv coding scheme for motion video that uses intraframe encoding, but interframe decoding. <s> BIB001 </s> Distributed video coding for wireless video sensor networks: a review of the state-of-the-art architectures <s> DVC architectures <s> In current interframe video compression systems, the encoder performs predictive coding to exploit the similarities of successive frames. The Wyner-Ziv Theorem on source coding with side information available only at the decoder suggests that an asymmetric video codec, where individual frames are encoded separately, but decoded ::: conditionally (given temporally adjacent frames) could achieve similar efficiency. We propose a transformdomain Wyner-Ziv coding scheme for motion video that uses intraframe encoding, but interframe decoding. In this system, the transform coefficients of a Wyner-Ziv frame are encoded independently using a scalar quantizer and turbo coder. The decoder uses previously reconstructed frames to generate side information to conditionally decode the Wyner-Ziv frames. Simulation results show significant gains above DCT-based intraframe coding and improvements over the pixel-domain Wyner-Ziv video coder. <s> BIB002
As discussed in "Information theory of PVC and DVC", it is theoretically possible to achieve a coding efficiency comparable to that of conventional PVC paradigm when two sources encoded their correlated video sequences independently and decoded them jointly by exploiting the statistical correlation. However, the theorems have not identified the methodology to attain practically the same compression efficiency. Hence, researchers have devised their own implementation of DVC codecs with various different side information generation methods. For example, some codecs use the same DVC encoder while others employ the conventional PVC encoders (Intra mode) to generate side information. Practically, the compression efficiency of DVC codecs is comparable to PVC codecs (executing in Intra-mode) . Two primary DVC approaches have been proposed in literature, namely Berkeley  and Stanford (Girod et al. 2005; BIB001 BIB002 ) video coding architectures. The Berkeley architecture known as PRISM followed a block-based encoding approach with motion estimation module at decoder. On the other hand, the Stanford architecture adopted a frame-based encoding approach, which has gained much popularity because of its comparatively better rate-distortion performance. Subsequently, enhancements were made to the original design such as the extension of pixel domain Wyner-Ziv (PDWZ) to transform domain Wyner-Ziv (TDWZ), replacement of turbo codes by LDPC channel codes, development of more efficient reconstruction algorithms, and employment of Intra-frame coding mode from state-of-the-art PVC architectures for more efficient generation of side information. In the following section, we discuss the three main DVC architectures as mentioned above in more detail, namely PRISM  , PDWZ BIB001 , and TDWZ BIB001 BIB002 codec.