Adaptive multimedia stream presentation in mobile computing environment

We present a mechanism of multimedia synchronization for smooth play back of streams in a mobile environment. This mechanism contains an effective buffering method and playout control not only to provide seamless playback of a media stream, but also to minimize the effect of wireless network characteristics. To implement this in a mobile computing environment, we adopted a proxy concept for separating wireless and wired networks. This proxy puts the streams into the buffers from a server and sends them to mobile hosts. It does QoS negotiation with user applications if the network cannot support the required QoS. The proposed buffering method keeps the continuous play of a media stream using a feedback mechanism and playout control provides more natural multimedia presentation by adjusting the frame duration on-screen. Experimental results show that our synchronization scheme provides a constant playback rate even in the frequent short time disconnection and some buffering control parameters affect playback performance by some degree.