Transmission of aggregate VoD streams using playback rate

In video-on-demand (VoD) systems, using the entire frame-size sequence for each video stream, the VoD service provider can derive a video transport schedule which will cause neither buffer overflow nor buffer starvation without requiring excessive amounts of network bandwidth and buffer space. Specifically, such a transport schedule uses temporal averaging to reduce the rate variability of a video stream. We propose a simple and efficient VBR VoD-stream transport mechanism called the play-back rate transport with minimum rate guaranteed (PBRT-MRG), which exploits statistical multiplexing as well as temporal averaging. The proposed scheme provides statistical loss guarantees (instead of absolute loss-freedom guarantees) to maximize network utilization. Temporal averaging is done through buffering both at the server and at receivers. To exploit the advantages of statistical multiplexing, a set of VoD streams are multiplexed onto a common transport channel. For the aggregated video streams which are averaged temporally and spatially, we present a simple transport mechanism and a call-admission scheme both of which together provide statistical loss guarantees. Our empirical study shows that one can provide a VoD service without requiring any complex control while achieving high bandwidth/buffer utilization at a reasonable build-up delay. In one case, the proposed scheme is shown to save buffer requirement by as much as three orders of magnitude for the same bandwidth usage