Adaptive video streaming for embedded devices

Recent advances in mobile equipments and wireless communications are making the Internet increasingly heterogeneous in terms of network, hardware and software capacities. Moreover, resources availability on the Internet varies unexpectedly. Thus, providing an efficient access to multimedia services requires that multimedia streams be adapted according to the environment constraints. One approach to this issue is based on the use of intermediate nodes within the network to perform such adaptations (media transformations, protocol conversion, and data transcoding) thus minimizing intrusivity with respect to legacy applications. Many research works have followed this approach, but they lack the flexibility required to fully address the issue. In this purpose, we designed and implemented a framework for network-based adaptations of multimedia streams. To reach the required flexibility, this framework provides support for dynamic configuration and reconfiguration of adaptations processes. A language called APSL (Adaptation Proxy Specification Language) allows the specification of such (re)configurations. A specification is translated into a component-based software architecture which evolves dynamically according to execution conditions. We describe the implementation of this framework on top of the Microsoft DirectShow® environment and report on a performance evaluation which demonstrates the effectiveness of the approach.