Wyner-Ziv video coding with block classification

Abstract

Wyner-Ziv (WZ) video coding, or lossy coding of video with decoder side information (SI), is a new video coding paradigm which provides the potential of shifting encoder complexity to decoder. Due to the fact that correlation among adjacent frames varies spatially and temporally in a video sequence, in WZ video coding, the quality of SI generated at the decoder also varies accordingly. This implies that more parity bits should be sent for locations where the quality of the SI is poor, while fewer parity bits for locations where the quality of the SI is good. For this reason, this paper proposes a WZ video coding scheme with block classification. In the scheme, according to difference between blocks in a WZ frame and its adjacent key frame, the blocks in a WZ frame are classified into classes of different importance. A strategy is designed so that the more important a class is, the more bits will be transmitted for it, and this leads to savings in bit rate. Simulation on various test video sequences shows that, compared to a similar scheme without block classification, the proposed scheme can achieve a bit rate savings of up to 42.44% with only slight PSNR loss in some cases.