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Buffer Sharing Schemes for

Continuous-Media Systems?

Dwight J. Makaroff and Raymond T. Ng

Department of Computer Science

University of British Columbia

Vancouver, B.C., V6T 1Z4



Buffer management in continuous-media systems is a frequently studied topic. One of the most interesting recent proposals is the idea of buffer sharing for concurrent streams. As analyzed in [8], by taking advantage of the temporal behaviour of concurrent streams, buffer sharing can lead to a 50% savings in total buffer space. In this paper, we study how to actually implement buffer sharing. To this end, we develop the CES Buffer Sharing scheme that is very efficient to implement, and that permits savings asymptotically very close to the ideal savings predicted by the analysis in [8]. We show that the CES scheme can operate effectively under varying degrees of disk utilizations, and during transition periods when the number of concurrent streams changes. We also demonstrate how the scheme can be further improved, particularly for situations when the number of concurrent streams is small. In ongoing work, we will integrate the proposed scheme into a distributed continuous-media file system which is under development at the University of British Columbia.

1 Introduction

The advances in networking and storage technologies in the past decade have made multimedia computing possible. Providing effective multimedia support in information systems has naturally become a topic of great interest and practical value. For a multimedia information system to work well, however, it must deal with two major properties of or challenges presented by multimedia data. First, audio and video data are delay-sensitive. As recording and playback of video and audio data are continuous operations, once an information system starts displaying audio or video data, it must guarantee that enough resources are

?Research partially sponsored by NSERC Grants OGP0138055 and STR0134419, IRIS-2 Grants HMI-5 and IC-5, and CITR Grant on Distributed Continuous-Media File Systems."