Studying the Feedback Channel in Transform Domain Wyner-ziv Video Coding *

Wyner-Ziv (WZ) video coding – a particular case of distributed video coding (DVC) – is a new video coding paradigm based on two major Information Theory results: the Slepian-Wolf and Wyner-Ziv theorems. Recently, practical WZ video coding solutions were proposed with promising results. Many of the solutions available in the literature make use of a feedback channel (FC) to perform rate control at the decoder. In this context, this paper intends to analyse the impact of the feedback channel in transform domain WZ video coding, notably through a number of metrics such as the frequency the feedback channel is used as well as its associated rate. Also a study is presented on the quality evolution of the decoded frames as more parity bits are requested via the feedback channel. Finally, the codec performance is also analyzed in terms of the compression factor at bitplane/band level. Analysing the behaviour of the metrics above is important not only to understand the feedback channel impact but also to design new tools to improve the overall codec performance.