Quality Adaptation for Congestion Controlled Video Playback over the Internet
Reviewer: Jie Zhou
Internet has been experiencing explosive growth of audio and video streaming. To ensure fairness among applications, the streaming applications have
to adopt effective congestion control mechanism. However, the congestion control mechanisms usually will cause varying available bandwidth. Since
rapid fluctuation of quality is very disturbing to users, how to avoid it while performing congestion control becomes an important issue.
The paper presents a mechanism for using layered video in the context of unicast congestion control. This quality adaptation mechanism bridges the gap
between short-term changes in transmission rate and the need for stable quality in streaming applications.
Buffering can effectively help cope with short-term changes in bandwidth due to AIMD congestion control.
Increasing the smoothing factor can limit the frequency of quality variation.
This paper proposes an effect machanism for quality adaption in context of congestion control. It somehow contributes to the incorporation of congestion
control into streaming applications. So I give it rate 3 (modest contribution). Sound logic and mathematical analysis, together with extensive simulation
results, makes this paper quite convincing.
The mechanism is built on the assumption that the congestion control employs an additive increase, multiplicative decrease algorithm. If the dominant
congestion control is no longer AIMD in future, the mechanism will become invalid.
The paper chooses the Rate Adaptation Protocol as the underlying congestion control mechanism because it's properties are relatively simple to predict.
This is a good lesson. When studying some aspect of a subject, we'd better keep other aspects as simple as possible so that we can achieve our goal