Codec-agnostic Dynamic and Distributed Adaptation of Scalable Media

Today's Internet is accessible to diverse end devicesthrough a wide variety of network types. To react tothis diversity of usage contexts new media codecsinclude adaptation support in the codec design.Scalable media codecs enable to easily retrievedifferent qualities of the media content by simplydisregarding certain media segments. The MPEG-21Digital Item Adaptation (DIA) standard enablescodec-agnostic adaptation by specifying a set ofdescriptions in order to describe content adaptationpossibilities and usage context in the XML domain.This book extends the DIA approach towards dynamicand distributed environments. To achieve this novelmechanisms for fragmentation storage and transportof XML metadata are introduced. Additionally amechanism based on a novel binary header to enablecodec-agnostic adaptation is specified. This GenericScalability Header (GSH) enables codec-agnosticadaptation at a considerably lower performance costcompared to the DIA approach. An adaptation nodebased on these novel mechanisms is implemented andevaluated for several types of scalable media. Aconcluding discussion analyzes the results of theevaluation of both mechanisms.