A distributed multimedia document presentation involves retrieval of objects from the document server(s) and their presentation at the client system. The presentation of the multimedia objects have to be carried out in accordance with the specification of temporal relationships among the objects. The retrieval of multimedia objects from the document server(s) is influenced by the factors such as: temporal specification of objects presentations, throughput offered by the network service provider, and the buffer resources on the client system. Flexibility in the temporal specification of the multimedia document can help in deriving an object retrieval schedule that can handle variations in the network throughput and buffer resources availability. In this paper, we develop techniques for deriving a flexible object retrieval schedule for a distributed multimedia document presentation. The schedule is based on flexible temporal specification of the multimedia document using the difference constraints approach.

We show how the derived retrieval schedule can be validated and modified to ensure that it can work with the offered network throughput and the available buffer resources. (Also cross-referenced as UMIACS-TR-96-21)