Christian Timmerer

A Survey on Bitrate Adaptation Schemes for Streaming Media over HTTP accepted in IEEE Communications Surveys & Tutorial

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ITEC researcher Christian Timmerer co-authored a survey on bitrate adaptation schemes for streaming media over HTTP which has been accepted in IEEE Communications Surveys & Tutorial and will be available as open access. This journal covers all aspects of the communication field with an impact factor of 20.23 according to IEEEExplore.

The abstract is as follows and an early access version is available at https://doi.org/10.1109/COMST.2018.2862938. In this survey, we present state-of-the-art bitrate adaptation algorithms for HTTP adaptive streaming (HAS). As a key distinction from other streaming approaches, the bitrate adaptation algorithms in HAS are chiefly executed at each client, i.e., in a distributed manner. The objective of these algorithms is to ensure a high Quality of Experience (QoE) for viewers in the presence of bandwidth fluctuations due to factors like signal strength, network congestion, network reconvergence events, etc. While such fluctuations are common in public Internet, they can also occur in home networks or even managed networks where there is often admission control and QoS tools. Bitrate adaptation algorithms may take factors like bandwidth estimations, playback buffer fullness, device features, viewer preferences, and content features into account, albeit with different weights. Since the viewer’s QoE needs to be determined in real-time during playback, objective metrics are generally used including number of buffer stalls, duration of startup delay, frequency and amount of quality oscillations, and video instability. By design, the standards for HAS do not mandate any particular adaptation algorithm, leaving it to system builders to innovate and implement their own method. This survey provides an overview of the different methods proposed over the last several years.