Application of dual-mode control in the continuous playback of streaming media
双重控制策略在流媒体连续播放中的应用

Because of the limitations in the traditional sending-rate control and the play-rate control, it is difficult to eliminate the delay and the influence of network disturbances in the continuous playback of streaming media. To improve the performance of the play system, a dual- mode control is applied. An internal mode feedback control of the sending-rate in the source is adopted to overcome the adverse effect caused by the propagation delay; and a simple PID controller of playback-rate in the sink is adopted to control the buffer length of the sink. Experiments show that this scheme reduces the influence of asynchronization caused by the delays in transmission and the disturbances of network in playback, and clamps buffer length at a steady value around the target buffer occupancy, effectively preventing the play-pause in buffer underflow and the play-jump in buffer overflow. The variation of the sending-rate is reduced, which is helpful to reduce the network congestion. Compared with the existing methods, it exhibits better control performances in the continuous playback under large network disturbances.