A proxy-assisted adaptation framework for object video multicasting

Video multicast is a challenging problem due to the heterogeneous and best-effort nature of the Internet. In this paper, we present a novel video multicast framework that exploits the potential of object scalability offered by MPEG-4. Specifically, we introduce the concept of object transmission proxy (OTP), which filters incoming streams using object-based bandwidth adaptation to meet dynamic network conditions. Multiple OPTs can form an overlay network that interconnects diverse multicast islands with semi-uniform demands within each single island. We concur with the wisdom that an application best knows the utility of its data. Hence, the bandwidth-adaptation algorithm for the OTPs adaptively allocates bandwidth among video objects according to their respective utilities and then performs application-level filtering based on an effective stream classification and packetization scheme. Extensive simulation results demonstrate that our framework has substantial performance improvement over conventional bandwidth-adaptation schemes. It is particularly suitable for object-based video multicasting where the objects are of different importance.