A CONTROL-THEORETIC APPROACH TO RATE ADAPTATION FOR DYNAMIC HTTP STREAMING

Recently, dynamic adaptive HTTP streaming has been widely used for video content delivery over Internet. However, it is still a challenge how to switch video bitrate under time-varying bandwidth. In this paper, we propose a novel control-theoretic approach to adapt video segments in dynamic HTTP streaming. The rate control is based on a sink-buffer, which has an overflow-threshold and an underflow-threshold. The objective is to maximize the playback quality while keeping the receiver buffer from either overflow or underflow. Using control theory, we formulate this rate control scheme as a proportional (P) control system, which exists oscillations and steady-errors. Furthermore, we design a proportional derivative (PD) controller to improve its adaptation performance. The conditions for stability and settling time of the PD controller are also derived. Numerous experiment results demonstrate the effectiveness of our proposed PD control scheme for dynamic HTTP streaming.