A Framework for Dynamically Configurable and Reconfigurable Network-based Multimedia Adaptations

Abstract

The recent advances in mobile equipments and wireless communications are making the Internet more and more heterogeneous. Terminals vary in their network capacities (bandwidth, latency, etc.), hardware capacities (CPU, memory, screen size, etc.) and in their software capacities (data formats, communications protocols, etc.). On the other hand, this evolution adds to the dynamic nature of the Internet, where resources vary unexpectedly. Thus, providing an efficient access to multimedia services requires that multimedia data be adapted according to each terminal capacity. One approach to this issue is based on the use of intermediate nodes to perform such adaptations (media transformations, protocol conversion, and data transcoding). In this area, there has been much research work for tackling the various forms of heterogeneity. However, less attention has been paid to the dynamic configuration and the reconfiguration at run-time of such mechanisms. This paper addresses these two aspects and describes a framework for network-based adaptations in multimedia streaming applications. This framework relies on a language, named APSL (Adaptation Proxy Specification Language), allowing the specification of network-based adaptation processes and their mn-time behavior. The translation of this language is based on a component-based platform offering basic multimedia-related functionalities; composed dynamically in order to build an arbitrary configuration. Also, reconfigurations are facilitated through high-level component-related operations. This paper describes the architecture of the framework and shows through experimental evaluation the benefits of run-time reconfiguration.