Beyond the playlist: seamless playback of structured video clips

In this paper we introduce the design and implementation of seamless playback for video/audio in the Ambulant Player. The Ambulant Open SMIL Player is an open-source media player that supports SMIL 3.0. A typical SMIL multimedia presentation consists of a set of declarative references to video/audio clips, which are relative to each other in terms of temporal and spatial relationships. Unfortunately, the declarative nature of SMIL often imposes performance delays, as individual items are fetched and presented. In this paper, we discuss the design and implementation of a caching and prefetching scheme that avoids service interruption and eliminate switch delay among these clips. A collection of videos is thereby rendered as if they were continuously rendered from one media container on one media source. Experiments are carried out to validate that our techniques can significantly lower the start delay of media rendering and therefore realize the seamless playback of SMIL multimedia presentations.