A Context-based Content Adaptation Algorithm And Its Application In UPnPAV

With the rapid growth of multimedia content, the appearance of a great variety ofterminal devices and heterogeneous networks, the user satisfaction has to meet morestrict demands, and they want to enjoy better multimedia services anytime andanywhere, from many kinds of devices. This paradigm is called Universal MultimediaAccess (UMA).In order to achieve this goal, the necessity of multimedia adaptation emerges.Multimedia adaptation carries out changes in the multimedia content in order toenable its consumption in different terminals, operating with different access networksand satisfying the preferences of the environment and users as far as possible.However, multimedia system for home environments (e.g., UPnP AV) only providessome basic building blocks, and the content adaptation feature is not part of the AVframework. In order to provide users better multimedia experience, the multimediacontent must be adapted according to contexts.This paper studies content adaptation based on context in UPnP AV. CBCAA(Context-Based Content Adaptation Algorithm) is proposed. First the algorithmobtains and classifies context information; then builds the constraint model accordingto the different types of context information, constraint satisfaction method is used toacquire MDDS (Media Description Decision Set); finally a bit-stream adaptationengine transcodes the media from source media to object media based on MDDS.CBCAA enables UPnP AV adapt the content to environment and provides intelligentmultimedia services. Simulation results show the effectiveness of the algorithm.The innovation of this article is to take into account the various contextinformation of AV playback environment, and propose a context model based onMPEG-21DIA standard, then on the basis of this model perform the contentadaptation: convert content adaptation decision-taking into solving constraintsatisfaction problem. Finally, perform the transcoding based on MDDS, as a result meet requirements of user data transmission and improve the quality of multimediaexperience.Multimedia adaptation will play an important role in future multimedia servicesas it’s an important technology to achieve UMA, and UPnP AV is one of majorstandards of digital home multimedia system. Multimedia adaptation in digital home,though faces many challenges, is also a key issue to be resolved in realizingUMA. Based on existing research results, our work propose CBCAA and apply itto UPnP AV architecture. So this paper has certain theoretical value and practicalsignificance.