Probability updating for decoder and encoder rate control turbo based Wyner-Ziv video coding
In Wyner-Ziv video coding (WZVC), powerful error correcting codes must be used to achieve high compression efficiency; turbo codes are the most commonly used error correcting codes in WZVC. To improve the turbo coding performance in the context of WZVC, this paper proposes a probability updating technique (PUT) acting as an outer loop of the common turbo decoding operation. Whenever a turbo decoded bitplane is not error-free, the proposed technique attempts to correct bitplane errors by updating the correlation noise probabilities for the most likely in error bits, followed by turbo redecoding. The new tool is evaluated both in the context of encoder rate control (ERC) and decoder rate control (DRC) turbo based WZVC scenarios with average overall PSNR gains up to about 0.5 dB in ERC and average WZ rate savings up to about 6% in DRC.