| With the high development of wireless network, more and more mobile videoterminals are used in multimedia communications. Since these wireless devices arealways limited in computation capability and energy resources, the encoder should below-complexity and error resilient with high compression efficiency. The traditionalvideo compression standards such as MPEG and H.26x could not used in theabove-mentioned application environment because of the complicated encoder.Therefore, the scholars around the world proposed a novel video compression method,distributed video coding technology, especially Wyner-Ziv video coding has recentlybecomearesearchfocusofdistributedvideocoding.The influence of the key technologies such as rate control, side informationgeneration and correlation noise model on Wyner-Ziv video coding efficiency isanalyzed in the thesis. At first, a rate control algorithm without feedback is proposed,which allocates the frame-layer encoding bitrate according to the target bitrate and theinter-frame correlation, and a biteplane encoding rate control method without feedbackis used in the Wyner-Ziv frame encoding. The proposed algorithm avoids using thefeedback channel, which can guarantee real-time video communication. Then, theoverlapped block bi-directional motion compensation algorithm based on the originalimage correlation is proposed, namely uses the original video inter-frame correlation toassist motion estimation and smoothing at decoder, and generates side informationaccurately. The proposed method can greatly improve the quality of reconstructedframe.Finally, a practical Wyner-Ziv video coding system based on transform domain isconstructed using the above-mentioned algorithms, and correlation noise model isimplemented to assist rate control, side information generation and reconstruction.Experimental results show that compared with H.263+ intra-frame coding andH.264/AVC intra-frame coding method, the proposed Wyner-Ziv video codingefficiency is significantly improved and the reconstruction video quality is obviouslyenhanced, besides, the proposed system whose encoder is simple and easy to realize,can be applied to the video communication systems for low-complexity encodingterminals. |
