With the proliferation of networked devices, today’s multimedia applications operate, as never before, in heterogeneous and dynamic environments. An attractive way to deal with this situation is to make applications self-adaptive (or self-reconfigurable); that is, make them able to observe them-selves and their environment, to detect significant changes and to reconfigure their own behavior in QoS-specific ways. This issue has made the subject of numerous works, especially in the context of multimedia applications. However, several key requirements of adaptivity have not been well addressed such as: the generality to a wide range of applications, the customizability to each application context and the flexibility of reconfiguration mechanisms. We address these aspects in a component-based framework for building self-reconfigurable multimedia applications, named PLASMA. This paper describes the architecture of PLASMA and shows its use through an application use case. Experimental evaluations show that reconfigurations have a low cost, while significantly improving the QoS. 1.

Abstract. Distributed multimedia applications are very sensitive to resource variations. An attractive way for dealing with dynamic resource variations consists in making applications adaptive, and even self-adaptive. The objective is to grant applications the ability to observe themselves and their environment, to detect significant changes and to adjust their behavior accordingly. This issue has been the subject of several works; however the proposed solutions lack flexibility and a high-level support that eases the development of adaptive applications. This paper presents PLASMA, a component-based framework for building multimedia applications. PLASMA relies on a hierarchical composition and reconfiguration model which provides the expected support. The experimental evaluation shows that adaptation can be achieved with a very low overhead, while significantly improving QoS of multimedia applications as well as resource usage on mobile equipments. 1.

One of the most widely used media delivery technology across Internet is streaming. It enables users to receive multimedia content and provides some control functionality over the media. Videoconferencing technologies such as H.323, SIP and AccessGrid, provide audio and visual interactive environment to their clients. We have developed Global multimedia Conferencing System (Global MMCS), which is an integrated videoconferencing system that allows heterogeneous multimedia clients, such as H.323, SIP and AccessGrid, to join the same videoconferencing session. In this paper we present a web services based streaming gateway that enables RealStream clients to join the real-time videoconferencing sessions and receive multimedia content generated by other clients in the system.

Developing applications to control audio/video equipment and the interface between conventional audio/video signals and Internet streaming media is difficult. Consequently, widespread deployment and use of streaming media in day-to-day activities has been slow to develop. This paper describes a middleware system and application program interface designed to solve this problem. The system, called INDIVA, provides a hierarchical name space for accessing and controlling audio/video equipment, software services for processing media streams, and conference resources. The design and implementation of the system is described and examples are presented that illustrate how it can be used to implement direct manipulation interfaces for Internet streaming media. This middleware can also be used to implement control and automation systems for Internet webcasting and distributed collaboration systems. 1.