One way to broadcast a popular video is to use a number of dedicated channels, each responsible for broadcasting some portion of the video periodically in a predefined way. The stress on the channels can be alleviated, and new viewers do not have to wait long to start their playback. Many approaches falling in this category have been proposed. One such scheme that interests us is the fast broadcasting (FB) scheme, which can broadcast a video using k channels by incurring at most O(D/2/sup k/) waiting time on new-coming viewers, where D is the length of the video. We consider a set of videos, each being broadcast by the FB scheme. Since the demand levels on these videos may change with time, it is sometimes inevitable to change the numbers of channels assigned to some videos. We propose a novel seamless channel transition enhancement on top of the FB scheme to dynamically change the number of channels assigned to a video on-the-fly. Clients currently viewing this video will not experience any disruption because of the transition. A channel allocation scheme is also proposed based on the arrival rates of videos to minimize the average waiting experienced by all viewers. From the system manager's point of view, the enhancement will make the FB scheme more attractive.

One way to broadcast a popular video is to let multiple users share fewer channels. The stress on channel demand can be alleviated without sacrificing viewers' waiting time. One such scheme that interests us is the fast broadcasting (FB) scheme (Juhn et al., 1997, 1998), which can broadcast a popular video using k channels without keeping newcoming viewers waiting for more than O(D/2/sup k/) time, where D is the length of the video. In this paper, we propose two enhancements to the FB scheme. First, since the level of demand on a video may change by time, we show how to dynamically change the number of channels assigned to the video and seamlessly perform this transition. Clients currently viewing this video will not experience any disruption during the transition. Second, given a set of channels and a set of popular videos, we propose a scheme to assign these channels to the videos such that the average viewers' waiting time is minimal. From the system manager's point of view, these enhancements will make the FB scheme more attractive.