Turbo-slice-and-patch: an algorithm for metropolitan scale VBR video streaming

In recent years, a number of sophisticated architectures have been proposed to provide video-on-demand (VoD) service using multicast transmissions. Compared to their unicast counterparts, these multicast VoD systems are highly scalable and can potentially serve millions of concurrent users. Nevertheless, these systems are designed for streaming constant-bit rate (CBR) encoded videos and thus cannot benefit from the improved visual quality obtainable from variable-bit rate (VBR) encoding techniques. To tackle this challenge, this paper presents a turbo-slice-and-patch (TSP) algorithm to support VBR video streaming in a multicast VoD system. Results obtained from trace-driven simulation of 300 VBR videos show that serving VBR videos with the TSP algorithm increases the average latency by only 9% compared to the CBR case with the same average video bit rate. Moreover, in 165 out of the 300 video titles, the TSP algorithm actually outperforms the CBR equivalent by shortening the latency by 0.04%-99%. Given that we can achieve similar visual quality by encoding VBR video at half the average rate of CBR video, this TSP algorithm can potentially serve VBR videos with more consistent visual quality and with less resource compare to CBR-based video streaming systems.