Acrobat (25 KB)
Word (6 KB)Use of CommandDescriptors and CommandROUTEs to Support User Interaction
Contribution M3506, 43rd MPEG Meeting, Tokyo, Japan, March 1998
Summary
MPEG-4 supports two forms of user interaction with a presentation (scene); local interactivity and remote interactivity. Local interactivity can be fully implemented using the native event architecture of BIFS, as well as the BIFS update mechanism for events generated by a hosting application, scripts, and AAVS. Remote interactivity is interacting with a remote user (client and/or server). Remote interactivity is supported by means of control messages over the MPEG-4 systems back-channel. This section describes the use of CommandDescriptor and CommandROUTE mechanism to support user interaction. The control message that is sent back to the server is formatted into a Command that is encapsulated in a timestamped ALPDU. In this discussion, server refers to a peer in the session.