The goal is to investigate the minimum amount of knowledge needed by a proxy server for consistent caching of interactive multimedia scenes encoded in MPEG-4 systems.
We limit the interactive multimedia scenesto be of the type branching video. The caching scheme proposed is a specialization of partial caching. The extentof a branching video is the number of alternative branchesavailable to the user at a branching point.
The proposed caching scheme is extent domain caching.It works by limiting the number of alternative branchesstored in the cache. Cache misses are served from the source server to provide aservice transparent for the users.An implementation with test runs is provided. In the implementationthe interactivity is limited to building blocks of complete ES. For content with several alternative scenes within a single ES, a different approach is needed. The proxy have to construct ad hoc objects from the AUs that constitute thealternative scenes. These ad hoc objects should be identifiable andhave defined boundaries. Caching replacement decisions are then madeon the ad hoc objects, and not on the complete ES.Identities can be constructed from the sequencenumber of the AUs and the ES id. The boundaries can be found byanalysing where the users shift playback point.