Scalable live video streaming to cooperative clients using time shifting and video patching

We consider the problem of how to enable the streaming of live video content from a single server to a large number of clients. One recently proposed approach relies on the cooperation of the video clients in forming an application layer multicast tree over which the video is propagated. Video continuity is maintained as client departures disrupt the multicast tree, using multiple description coded (MDC) streams multicast over several application layer trees. While this maintains continuity, it can cause video quality fluctuation as clients depart and trees are reconstructed around them. In this paper we develop a scheme using the transmission of a single-description coded video over an application layer multicast tree formed by cooperative clients. Video continuity is maintained in spite of tree disruption caused by departing clients using a combination of two techniques: 1) providing time-shifted streams at the server and allowing clients that suffer service disconnection to join a video channel of the time-shifted stream, and 2) using video patching to allow a client to catch up with the progress of a video program. Simulation experiments demonstrate that our design can achieve uninterrupted service, while not compromising the video quality, at moderate cost