Research of the Virtual Dependency Channel in Distributed Video Coding

Abstract

The inherent non-stationary characteristic of video signal,such as occlusion phenomena,leads to a complicated motion-compensated prediction technology. In distributed video coding (DVC) because the decoder cannot have access to the current frame,modeling the temporal correlation noise becomes a difficult task. In order to reduce the performance degradation owing to the non-stationary characteristic of video signal,this paper focuses on the research of virtual dependency channel model. Based on a common DVC codec,this paper presents a generalized model of the virtual dependency channel,analysis of which shows that in transformation domain the different subbands have various degree of sensitivity to the temporal correlation noise. According to the analysis this paper proposes a novel VCMDWT model,in which the virtual dependency channel is modeled at the LL subband with property of being more stationary,at the same time the non-stationary high frequency subbans are encoded by SPIHT with intra mode. The simulation results show that the proposed model is especially adaptable to the frames with many occlusion areas,which would be unfit for the pixel domain DVC,and finally improves the rate distortion performance with a gain up to 2.6dBs.