Region-of-interest based coding scheme for synthesized video

In many multimedia applications, such as online speech, video chat and online conference, multiple source videos are synthesized in a single scene for explicit presentation and the synthesized video is compressed for transmission. The source video with important contents deserves more compression resources for quality preservation under the bandwidth constraint. To address this problem, a region-of-interest (ROI) based coding scheme for synthesized video is proposed in this paper aiming at achieve better and consistent quality for ROI source videos with the bitrate meeting the constraint bandwidth. In the proposed coding scheme, ROI based rate-distortion (R-D) models are established, in which different R-D models are built for different source video. Then an objective function is defined with respect to the video quality and the consistency of video quality. By minimizing the objective function, the optimal quantization parameters for the ROI and non-ROI source videos are obtained. The experimental results show that the proposed coding scheme achieves better and consistent quality for ROI source videos.