Adaptive Media Streaming - Scalable Continuous Media Streaming Systems - page 154

algorithm gives lower rebuffering ratio in most traces than the average-case performance of CR.
Averaging over all 94 traces, the AVS algorithm can achieve 20% lower rebuffering ratio than
the CR algorithm, while the average video bit-rate is only 0.7% lower than the CR algorithm,
showing that both algorithms can make efficient use of the network bandwidth.
Although the optimal rebuffering ratio of the CR algorithm is much lower, it requires offline
optimization which is impossible in practice. By contrast, the AVS algorithm does not require
any a priori knowledge of the network bandwidth available or tuning of any control parameter
and thus will be simpler to deploy.
8.7 Summary
In this chapter we presented a rate adaptation algorithm for streaming video over the Internet
which only supports best-effort service. The algorithm has two unique features to maximize
its compatibility with existing video player software. First, we showed that the rate adaptation
algorithm can be applied to streaming video over TCP/HTTP, which is compatible with most
of the existing video player software. Second, the rate adaptation algorithm performs net-
work bandwidth and client buffer occupancy estimations using only local information. Thus,
explicit feedbacks from the client are not needed and hence existing video player software
can be supported. Moreover, the presented algorithm does not need any parameter tuning or
a priori knowledge of the available network bandwidth to perform well, thus simplifying the
deployment of the adaptation algorithm in practice.
Note
1. Network traces used in the simulations belong to the NLANR project sponsored by the
National Science Foundation and its ANIR division under Cooperative Agreement No.
ANI-9807479, and the National Laboratory for Applied Network Research.
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