Wyner-Ziv coding refers to lossy source coding with side information at the decoder. Recently some practical applications of Wyner-Ziv coding to video compression have been studied 1-4 due to its advantage of error robustness over standard video coding standards. Based on recent theoretical result on successive Wyner-Ziv coding, 5,6 we propose in this paper a practical layered Wyner-Ziv video codec using the DCT, nested scalar quantizer (NSQ), and irregular LDPC code based Slepian-Wolf coding (or lossless source coding with side information). The DCT is applied as an approximation to the conditional KLT, 7,8 which makes the components of the transformed block conditionally independent given the side information. NSQ is a binning scheme that facilitates layered bit-plane coding of the bin indices while reducing the bit rate. LDPC code based Slepian-Wolf coding exploits the correlation between the quantized version of the source and the side information to achieve further compression. Different from previous works, an attractive feature of our proposed system is that video encoding is done only once but decoding allowed at many lower bit rates without quality loss.
