Computer Science Department
School of Computer Science, Carnegie Mellon University


Improving Fairness, Efficiency, and Stability
in in HTTP-based Adaptive Video Streaming

Junchen Jiang, Vyas Sekar*, Hui Zhang

June 2012


Keywords: Internet video, network measurement

Many commercial video players rely on some underlying bitrate adaptation logic to adapt the bitrate in response to changing network conditions. Past measurement studies have identified issues with today's commercial players with respect to three key metrics–efficiency, fairness, and stability–when multiple bitrate-adaptive players share a bottleneck link. Unfortunately, our current understanding of why these effects occur and how they can be mitigated is quite limited. In this paper, we present a principled understanding of bitrate adaptation and analyze several commercial players through the lens of an abstract player model. This helps us identify the root cause of several undesirable interactions that arise as a consequence of overlaying the video bitrate adaptation over HTTP and lead to poor efficiency, fairness, and stability. Building on these insights, we develop a set of techniques that can systematically guide the tradeoffs between stability, fairness and efficiency and thus lead to a general framework for robust video adaptation. We pick one concrete instance from this design space and demonstrate that it significantly outperforms all commercial players on all three key metrics across a range of experimental scenarios.

29 pages

*Intel Labs, Berkeley, CA

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