5. Concluding Remarks

The UMA promise of delivering multimedia content to a range of receivers with a range of capabilities is a challenging task. The diversity of receiver terminals, networks and content formats necessitates standardization. Representing content in all possible modalities and fidelities is impractical and resource intensive. Real time techniques to transcode content to different fidelities and transform content to different modalities is essential. Taking advantage of object-based representation of content is necessary to be able to scale content to suit the content playback environment. Efficient media transcoding techniques are needed to transcode media streams to appropriate formats. Content distribution should take into account distributed adaptation operations. Real time adaptation may not always be possible because of the processing overhead required for adaptation. The choice of real time adaptation vs. storing multiple variants of the content is largely application dependent. For large, general-purpose systems, real time adaptation is desirable. Session mobility is an important issue to enable seamless playback across clients as well as servers. Relatively small amount of research has been done in this area. Environment description and capability understanding is another key area. While there has been significant work in capability description, the amount of work in capability understanding/negotiation is limited.

Standardization, cooperative playback, content representation techniques, media transcoding and network resource renegotiation technologies are important factors determining how soon we can deliver the UMA promise.