Improved side information generation for distributed video coding

In distributed video coding, the side information is commonly generated by motion-compensated temporal interpolation of the neighboring reference frames at the decoder side. The side information quality has a strong impact on the final rate-distortion performance of the codec. In this paper, we propose a successive refinement after the decoding of each DCT subband to improve the accuracy of motion compensation between reference frames, in order to obtain a new side information estimation closer to the original Wyner-Ziv frame. Here, we propose two different algorithms in the refinement process of the side information. The experimental results show that the proposed techniques allow an improvement in rate-distortion performance that can reach 1.15 dB for GOP size of 2 and 3.2 dB for longer GOP size, with respect to state-of-the-art techniques, for sequences containing high motion.