Joint rate-distortion coding of multiple videos

Some communications applications involve the simultaneous transmission of multiple videos from one source location. We consider the optimal bandwidth allocation and coding of such co-located multiple videos for transmission over one constant bit rate channel. It turns out that a major issue consists in proper setting of target buffer levels, which arises due to the possibly large variation in the rate-distortion relations of the aggregate video material in a short time period. In fact, this is also an issue in MPEGx coding whose I, P, and B frames possess different rate-distortion characteristics. We outline an approach to optimal solutions under several common types of distortion measures. And we present two simplified techniques and some preliminary simulation results. The simulation results show that such joint bit allocation can significantly enhance the average coding performance over multiple videos.