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Paper on Skew detection and compensation for Internet audio applications

Orion Hodson Crowcroft presented our paper on Skew detection and compensation for Internet audio applications at the IEEE International Conference on Multimedia and Expo in New York this week.

Long lived audio streams, such as music broadcasts, and small differences in clock rates lead to buffer underflow or overflow events in receiving applications that manifest themselves as audible interruptions. This paper presents the low complexity algorithm used in RAT for detecting clock skew in network audio applications that function with local clocks and in the absence of a synchronization mechanism. A companion algorithm to perform skew compensation is also presented. The compensation algorithm utilises the temporal redundancy inherent in audio streams to make inaudible play-out adjustments. Both algorithms have been implemented in a simulator and tested in the real-world as part of the Robust Audio Tool. They perform effectively over the range of observed clock rate differences and beyond.