MPEG-4, under the auspices of the ISO, is specifying tools to enable object-based audio-visual presentations. These include tools to encode individual objects, compose presentations with objects, store these object-based presentations and access these presentations in a distributed manner over networks. The main distinguishing feature of object-based audio-visual presentations is the scene composition at the user terminal. The objects that are part of a scene are composed and displayed at the user end as opposed to encoding the composed scenes as is done in the case of MPEG-2. Such object-based representation and presentation has several benefits including compression efficiency and interaction with individual objects.

Mobile Cloud Computing refers to mobile services that use the computing resources and data on the cloud to provide a requested service. A request from a mobile client leads to a process in the cloud that operates on the data in the cloud and the result of this processing is returned to the mobile client. The main reasons for using the cloud to deliver mobile services are lack of sufficient computing and data resources on the mobile client This cloud computing model works especially well for mobile devices and enables services that are not otherwise possible because of limited computing and communication resources. Cloud computing can also improve the energy performance of mobile applications when computationally intensive tasks are off loaded to the cloud.

We describe the implementation of a streaming client-server system for object-based audio-visual presentations in general and MPEG-4 content in particular. The system augments the MPEG-4 demonstration software implementation(IM1) for PC's by adding network-based operation with full support for the Delivery Multimedia Integration Framework (DMIF) specification, a streaming PC-based server with DMIF support (via Xbind Inc's XDMIF suite), and multiplexing software. We describe XDMIF, the first reference implementation of the DMIF specification. The MPEG-4 server is designed for delivering object-based audio-visual presentation. We discuss the issues in the design and implementation of MPEG-4 servers. The system also implements a novel architecture for client-server interaction in object-based audio-visual presentations, using the mechanism of command routes and command descriptors. This new concept of command routes and command descriptors is useful in developing sophisticated interactive applications.