DIVeR: a dynamic interactive video retrieval protocol for disk array based servers

Video-on-demand (VOD) is a very promising multimedia application of the near future. In order for such a service to be commercially viable, efficient storage and retrieval schemes need to be designed. Grouping MPEG frames into segments and retrieving segments instead of individual frames can result in a more efficient use of disk retrieval resources. In conjunction with efficient scheduling protocols for handling multiple users, a large number of users can be supported resulting in a more cost-effective system with good quality of service (QoS). Our contribution in this paper is two-fold: we propose a scheme for grouping MPEG frames into segments wherein no frames are discarded during fast playback (with segment skipping) due to the unavailability of other frames needed for their decoding. The grouping scheme can handle any desired segment size and the fast playback rate can also take on any desired value. We propose the dynamic interactive video retrieval (DIVeR) protocol, a protocol for scheduling the retrieval of multiple users from disk-array servers. DIVeR has a low interactive latency while supporting a large number of users at a high QoS. Two variations, DIVeR-2 and DIVeR-3, are discussed. Numerical results utilizing both schemes are provided using data from an MPEG coded video of Star Wars and a model of the Seagate Barracuda disk