Region-of-interest Based Rate Control Scheme For Synthetic Video

Synthesized video consist of multiple source videos, and has been widely usedin many kinds of Internet applications, such as online video chat, online conference.In such applications, some source videos many be more important than others, suchas the speaker in the online conference, these sources will be regard as ROI (Regionof interest), while other sources are regard as non-ROI. It is obvious that when thebandwidth is limited, the quality of ROI should be assigned a high priority while thequality should keep consistency and not wave too much.For all the above reasons, a ROI rate control scheme for synthesized video isproposed in this paper. To get the accurate cost of each source, rate-distortion (R-D)models with different parameters are assigned to different sources。To improve thequality of ROI, the encoder will use a low QP encoding ROI, and a higher QPencoding non-ROI. Considering the consistency of ROI, to optimally choose thequantization steps corresponding to the ROI and non-ROI sources, an target functionthat combines quality and consistency is employed, the optimal values of QP areobtained by minimize the objective function. This scheme is implemented onH264/AVC reference software JM15.1and the experimental results show that theproposed scheme perform better visual quality and improve the consistency of qualityin ROI when compared to JM15.1.