Layered multicast has been shown as a promising technique for dis-tributing a video program to a potentially large number
of heterogeneous re-ceivers. While several layered multicast approaches have been proposed, prior work has almost exclusively
focused on improving the perceived video quality in terms of PSNR value or/and the fairness among different receivers. In
this paper, we first argue that stability is another major index for the video playback quality; in an extreme case even with
the best possible achievable PSNR value, the frequent switching between different layers still can lead to significant qual-ity
degradation. We then introduce an end-to-end adaptation framework that improves the stability and fairness for receivers by
employing a dynamic layer rate allocation scheme on the sender’s side. Specifically, we propose a new metric, called Stability-aware
Fairness Index (SFI), which can capture both the stability as well as fairness. We then formulate the optimal layer rate allocation
problem with the objective of minimizing the expected SFI for all the receivers in a multicast session, and derive an efficient
algorithm to solve the problem. Simulation results demonstrate that our scheme can significantly improve the degree of stability
and fairness, thus leading to better video playback quality.
This research was supported in part by grants from Research Grant Council (RGC) under con-tracts AoE/E-01/99, HKUST6196/02E
and N_HKUST605/02.
J. Liu’s work is partially supported by a Microsoft fellowship.
3 J. Zhang’s work is partially supported by a Microsoft fellowship.