Specification and support of adaptable networked multimedia

Accessing multimedia information in a networked environment introduces problems that do not exist when the same information is accessed locally. These problems include: (1) competing for network resources within and across applications, (2) synchronizing data arrivals from various sources within an application, and (3) supporting multiple data representations across heterogeneous hosts. Often, special purpose algorithms can be defined to deal with these problems, but these solutions are usually restricted to the context of a single application. A more general approach is to define an adaptable infrastructure that can be used to manage resources flexibly for all currently active applications. This paper describes such an approach. We begin by introducing a general framework for partitioning control responsibilities among a number of cooperating system and application components. We then describe a specification formalism that can be used to encode an application's resource requirements, synchronization needs, and interaction control. This specification can be used to coordinate the activities of the application, the operating system(s) and a set of adaptive information objects in matching the (possibly flexible) needs of an application to the resources available in an environment at run time. The benefits of this approach are that it allows adaptable application support with respect to system resources and that it provides a natural way to support heterogeneity in multimedia networks and multimedia data.