Priority Dropping for Scalable Video

For H.264/SVC, different layers or frames have different order of precedence according to their importance on video quality and the decoding process. Network should provide more protection for high priority layers or frames when SVC stream is transmitted over IP network. This paper proposes an active queue management algorithm based on priority dropping and PID algorithm, called PID_PD, which first drops the least important packets when network congestion arises. PID_PD implements differentiated service in IP layer to provide high quality video for end user. In addition, PID_PD does not create a side effect for the performance of control system. In this paper, we use BCC (Binomial Congestion Control) as source rate control protocol. BCC and PID_PD form a close-loop control system. By using a classic control theoretic approach to analyze the stability of the close-loop system, we present a method to decide the PID_PD parameters. Simulation shows PID_PD can protect important video data well, lower the disturbance of background flow, and decrease the packet loss rate of SVC flow.