COSMOS: Collaborative system framework based on MPEG-4 objects and streams.

Abstract

In this thesis, a new collaborative framework has been developed, based on the specifications of the MPEG-4 standard. The framework provides access to the content of the scene, which is constructed in a directed acyclic graph. The scene is compressed and streamed using the MPEG-4 Binary Format for Scene (BIFS) specifications. In addition, VRML files are supported and translated to BIFS. The rendering of the scene is based on Java 3D. Media streams like audio and video are also rendered in the same scene with the 3D content. They can be rendered in the surface of every shape. The Java Media Framework (JMF) is used to decode and encode the audio-visual streams, and it is extended to enable their rendering in the 3D scene. The transmission of the media streams among the participants of the shared environment is over the RTP protocol, using multicast delivery. JMF provides an implementation of the RTP protocol. This implementation is extended to provide a reliable multicast transmission protocol for the exchange of critical content, like the BIFS stream. (Abstract shortened by UMI.)