On the interactions between layered quality adaptation and congestion control for streaming video

This paper uses analysis and experiments to study the impact of various congestion control algorithms and receiver buffering strategies on the performance of streaming media delivery. While traditional congestion avoidance schemes such as TCP’s additive-increase/multiplicativedecrease (AIMD) achieve high utilization, they also cause large oscillations in transmission rates that degrade the smoothness and perceptual quality of the video stream. We focus on understanding the interactions of a family of congestion control algorithms that generalize AIMD, with buffer-based quality adaptation algorithms for hierarchically-encoded and simulcast video. Our work builds on and extends the results of Rejaie et al. [19]; we find that the combination of a non-AIMD algorithm that has smaller oscillations than AIMD and a suitable receiver buffer allocation and management strategy provides a good combination of low playout delay and TCP-friendly congestion control. The paper describes these mechanisms and the results of experiments conducted using a prototype video server for MPEG-4 video, showing that our approach can improve the interactivity and adaptivity of Internet video.