Research On Stereoscopic Video Coding And Rate Control

Compared with 2D video, 3D video succeeded in creating more realistic impressions of natural 3D scenes. 3D video is currently attracting increasing interest,as it provides users a more involving and immersive representation of visual information, and to provide more natural methods of communication. Rate control plays a critical role in the 3D video applications. It select the best quantization parameter for each frame to regulate the coded bit stream to satisfy certain given conditions, on the one hand, and enhances the compression efficiency and quality of service of standard video coders, on the other hand. In this thesis,we focus on improving the quality and compression efficiency of real time 3D video applications by encoder design and rate control scheme optimization.Firstly, the vision principle of 3D video and the key technology of stereoscopic video coding are introduced.A real time 3D video encoder is implemented based on H.264 with disparity and motion estimation,which does not use the latter frames information when encoding current frame. It also has backward compatibility with current 2D video codecs. By analysis of the drawback of the existing rate.control algorithm, a new rate.control algorithm based on frame complexity and importance (CI) for H.264/AVC video coding is presented. Compare the proposed CI.based rate.control algorithm with JVT-G012 recommended by H.264/AVC by using the software JM10.1, the compression efficiency and quality of service of video coder is improved.Secondly, in order to set an arbitrary network bandwidth for each viewpoint, an independent rate control scheme is presented,which set a separate buffer for each viewpoint (SBRC).This scheme aim to accurately calculate QP of B frame, which is simply computed by interpolation of other picture in conventional rate.control algorithms for single view videos.A date switching strategy is used to realize the alternation control of left and right viewpoint. The results show that the proposal rate control algorithm can further improve PSNR compared with Fixed QP strategy, while the the bit rate error does not exceed 1%,the average bit rate error is about 0.3%. The proposal rate control algorithm can further improve the compression efficiency. In this platform, lots of tests are conducted show the best proportion of the left and right bandwidth.In addition ,in order to full use of the redundancy information in stereoscopic video, an joint rate control scheme is presented,which set a unified buffer for the stereo viewpoint(UBRC). UBRC see a stereo pairs as a unit in allocating bandwidth. In stereo pairs ,MAD is used as the allocated factor. The results show that the proposal rate control algorithm can further improve PSNR compared with SBRC algorithm, while the BDPSNR of them is similar. Finally a reasonable factor to describe frame complexity and importance of each stereo pairs and frame is used in adaptive allocation target bits and buffer strategy among different frames. The results show that the proposal rate control algorithm(I-UBRC) can further improve the compression efficiency and quality of decoder video of standard video coders, compared with SBRC algorithm,UBRC algorithm and Fixed QP strategy.