Design and performance study of scalable video storage in a disk-array-based video server

This paper explores a data placement method based on rate staggering to store scalable video data in a disk-array-based video server. Scalable video means a video which is coded in such a way that subsets of the full video bit stream can be decoded to create low quality/resolution videos. Supporting layered multiple resolutions from a video server is very desirable in many applications. Note that in a disk array the video data corresponding to different rates of the same video clip are not required to reside in the same disk. In view of this, we propose and explore in this paper the approach of rate staggering, i.e., staggering video data in the disk array based on data rates. It is noted that the advantages of the proposed rate staggering method enable a video server to provide feasible solutions to some video stream requests which cannot be met otherwise. The system throughput can thus be increased. Performance studies on the methods proposed are conducted. It is empirically shown that a VOD system employing rate staggering can significantly outperform a system employing time staggering for the playout of scalable video.