The free viewpoint switching is one of the most important features of multi-view video streaming. The key problem lies in how to achieve the best performance when the camera processing capability and the network bandwidth are limited. In this paper, we propose a novel free viewpoint switching scheme for multi-view video scenario, in which the distributed video coding technique is employed. In this scheme, the multi-camera video sources are encoded separately with the traditional hybrid video coding scheme, and meanwhile an alternative bitstream is produced for every frame based on the Wyner-Ziv coding method for the purpose of error correction when the viewpoint switching occurs. When switching happens, the Wyner-Ziv bits corresponding to the actual reference frame at the switching point is transmitted and used to recover the true reference. Instead of completely removing the mismatch, the proposed switching scheme tries to reduce the mismatch to an acceptable level so as to save the bits for the switching frame. A wavelet transform domain Wyner-Ziv coding method is proposed to produce the Wyner-Ziv bits for the switching frame. Conclusively, with the proposed scheme, the inter-camera communication can be avoided and the drifting error can be controlled efficiently when the viewpoint switching occurs.
There are mainly two key points which can affect the efficiency of multi-view video capture and transmission system largely: communication between cameras and computing complexity of encoder. In this paper, we propose a practical framework of distributed multi-view video coding, in which inter-camera communication is avoided and the large computing complexity is moved from encoder to decoder. In this scheme, multi-camera video sources are encoded separately and decoded dependently, and the traditional inter frame is replaced by Wyner-Ziv frame. To reach this goal, Wyner-Ziv theory on source coding with side information is employed as the basic coding principle. A Wyner-Ziv coding method based on wavelet transform and turbo codes is used as the core of the scheme. To further improve the coding performance, we also consider exploiting the large redundancy between adjacent views. A more flexible prediction method that can jointly use temporal and view correlations is proposed to generate the side information at the decoder. The experimental results show that the coding performance of proposed DMVC scheme is very promising compared to the traditional intra coding.