Distributed SIP conference management with autonomously authenticated sources and its application to an H.264 videoconferencing software for mobiles

Abstract

The design of conferencing systems for achieving efficient and flexible communication in a fully distributed, infrastructure-independent fashion is a promising direction, both in terms of research and practical development. In the particular case of video communication, the seamless adaptation to heterogeneous mobile devices poses an additional strong challenge to those seeking for interoperable and easy-to-deploy solutions. In this paper, we make several contributions towards a generic peer-to-peer (P2P) videoconferencing solution that extends into the mobile realm. We describe the essential building blocks for conference management and media distribution that are necessary for a distributed conferencing approach. Establishing a distributed SIP conference focus, participants share the conference according to their individually given capabilities and resources in terms of bandwidth and processing power rather than in a centralized and fixed way. Overall concepts and SIP-primitives for such an autonomous organization are presented. Security issues that derive from this decentralized identity management are resolved by so-called \em Overlay AuthoCast, a novel use of cryptographically generated identifiers. Furthermore, this work is dedicated to the development of a software-based H.264 video codec implementation and the specific aspects resulting from tuning such a highly resource-intensive software codec to the given target platform of a standard consumer smartphone.