Flexible Complexity Control Solution for Transform Domain Wyner-Ziv Video Coding

Most Wyner-Ziv (WZ) video coding solutions in the literature focus on improving the coding efficiency. Recently, a few papers have addressed problems related to the complexity distribution of WZ video coding by sharing the motion estimation process between the encoder and decoder. However, these methods turn out to significantly increase the computational complexity of the encoding process, due to the presence of motion estimation at the encoder, which is less appealing in WZ coding applications, since their primary requirement is a low-encoding complexity. To address this problem, we propose a different approach to complexity control based on the adaptive selection between WZ and intra coding in the WZ frames. This solution is more flexible than the previous ones in that it can be implemented either at the encoder or decoder. The proposed intra mode selection algorithm exploits the spatial and temporal coherency in the transform domain Wyner-Ziv video coding (TDWZ), in order to achieve complexity control between the WZ encoder and decoder. The experimental results illustrate that the proposed algorithm not only effectively distributes the computational complexity over the encoder and decoder, but also retains the low-complexity feature at the encoder. This should make it attractive for a large number of real video applications of the WZ video coding paradigm. Moreover, the coding efficiency of the conventional TDWZ codec without intra mode decision is improved by up to 2 dB by the proposed intra mode selection algorithm.