Retrieval Scheduling for Collaborative Multimedia Presentations

We address the issue of retrieval scheduling of objects composing multimedia presentations, over networks that provide guaranteed Quality of Service (QoS). Clients going through a multimedia presentation can dynamically interact by requesting for reverse presentation or skip time duration. These operations can be efficiently handled if the client's buffer space can be utilized well. In this paper, we propose an algorithm for distributed multimedia information retrieval, and prove it to be optimal in terms of client buffer utilization. Using this algorithm we can maximize the number of objects that can be held in a client buffer of a given size. Hence, this algorithm also has the advantage of handling dynamic user interactions such as reverse presentation and skip efficiently, by minimizing the number of network accesses that need to be made. In environments where multimedia objects are replicated over a set of sources, this algorithm identifies the source that utilizes client buffer optimally. We also present details of a Collaborative Multimedia Presentation Platform that we have developed based on our algorithms.