A scalable bit-stream packetization and adaptive rate control framework for object-based video multicast

Layered and agent-based transmission schemes have been recommended as the solutions to the inherent heterogeneity problem of video multicast over the Internet. Such schemes either require the integration of a scalable codec and a layered transport protocol, or involve computationally intensive transcoding at the application level. In addition, how to support user interactions for object-based video applications (e.g., MPEG-4) has seldom been considered. To address these problems', we present a novel framework specifically designed for object-based video multicast. First, we propose a novel bit-stream re-organization and packetization scheme by taking advantage of the error resilience and concealment features in the MPEG-4 object-based codec. Second, we introduce the concept of a Video Transmission Agent (VTA) that eliminates the need for application level transcoding and works well with network-level rate control algorithm. We demonstrate that the combination of such approaches not only enables adaptive rate control more efficiently but also significantly reduces system complexity.