On Achieving Short Channel Switching Delay and Playback Lag in IP-Based TV Systems

摘要

IP-based TV systems are widely used to stream video content on the Internet. Compared with the traditional broadcast TV systems, IP-based TV systems suffer from much longer channel switching delays. In this paper, we propose a new IP-based streaming framework, called fast IP-based TV (FIPTV), to achieve close-to-zero channel switching delay at the price of extra download bandwidth and increased playback lags. In FIPTV, other than the channel being watched, a client also downloads an extra combination virtual channel, called backing united stream (BUS), which consists of video segments sequentially sampled from a set of target channels that a client might switch to in the near future. Video segments downloaded from the combination channel will be cached in a local buffer. When the client issues a channel switch request to a target channel, the client will immediately playback the most recently downloaded video of the target channel, leading to close-to-zero channel switching time, but a positive playback lag. Through analysis and simulations , we show that short average playback lag can be achieved across all channels through carefully designed channel scheduling algorithms on the BUS channel by considering channel popularity. We implement the proposed streaming framework in real systems. Through experiments on the Internet, we show that the actual channel switching delay can be reduced to less than 0.25 seconds, which is much shorter than that of the popular Internet video streaming services.