A Storage and Retrieval Technique for Scalable Delivery of MPEG-Encoded Video

Abstract

Concurrent retrieval of continuous media from a physical storage device can be achieved by interleaving data and providing a suitable scheduling algorithm. Scheduling approaches that exploit gains from statistical multiplexing are susceptible to a nonzero probability of frame loss due to the variable-bit-rate characteristic of compressed video. With interframe encoding schemes (such as specified by the MPEG standard), the losses propagate, resulting in a net loss of frames that exceeds the fraction of lost data. In this paper, we describe a mechanism for the storage and retrieval of MPEG-encoded video from a single disk storage system. The scheme balances the need for the reliable delivery of MPEG frames with the desire to support the largest number of sessions. Our approach reorganizes the MPEG-encoded video stream based on the relative importance of the frames and maps them to the storage device geometry. The reorganization reduces the impact of frames lost due to missed deadlines and distributes the frame losses over time and among sessions. Simulation results show that the new approach improves performance when compared to conventional storage and scheduling schemes.