Multiple Descriptions in the Wyner-Ziv Setting

We propose a new scheme of multiple descriptions in the Wyner-Ziv setting (MD-WZ). The two side decoders of MD-WZ use two different side information (SI) streams. Both SI streams are available to the central decoder, but none to the encoder. We derive an achievable region (inner bound) for this MD-WZ system for general source and SI. If the source and SI are correlated Gaussian and for quadratic distortion metric, the tight bound is obtained. Our result is an extension of Ozarow's result on multiple descriptions of Gaussian source without SI. The MD-WZ coding scheme is shown to have a property of practical significance. For symmetric case where the joint distributions of the source and the two SI are the same and the two channels are balanced, interchanging the two channels causes no performance loss for Gaussian source. Considering that the existing multi-description video coding methods suffer from the notorious drifting problem induced by channels interchange, this work lends a theoretical support to distributed multi-description video coding in the Wyner-Ziv setting.