Based on recent works on Wyner-Ziv coding (or lossy source coding with decoder side information), we consider
the case with noisy channel and addresses distributed joint source-channel coding, while targeting at the important application of scalable video transmission over wireless networks. In Wyner-Ziv coding, after quantization,
Slepian-Wolf coding (SWC) is used to reduce the rate. SWC is traditionally realized by sending syndromes of a
linear channel code. Since syndromes of the channel code can only compress but cannot protect, for transmission
over noisy channels, additional error protection is needed. However, instead of using one channel code for SWC
and one for error protection, our idea is to use a single channel code to achieve both compression and protection.
We replace the traditional syndrome-based SWC scheme by the parity-based one, where only parity bits of the
Slepian-Wolf channel code are sent. If the amount of transmitted parity bits increases above the Slepian-Wolf
limit, the added redundancy is exploited to cope against the noise in the transmission channel. Using IRA codes
for practical parity-based SWC, we design a novel layered Wyner-Ziv video coder which is robust to channel
failures and thus very suitable for wireless communications. Our simulation results show great advantages of the
proposed solution based on joint source-channel coding compared to the traditional approach where source and
channel coding are performed separately.
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 due to its advantage of error robustness over standard video coding standards. Based on recent theoretical result on successive Wyner-Ziv coding, 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, 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.