Capacity Requirements of Video Servers in Broadcast Television Facilities

Abstract

Digital video servers are rapidly being adopted in broadcast transmission facilities where new materials must be cached to these servers, usually from tape media or, possibly, from media in an archival system. To deal with the finite capacity of these servers (usually with hard disk media), old materials must be purged. In this process, materials of different time duration are handled. Increasingly, materials with different data rates are also handled because of the use of different compression standards, compression ratio, and (with the advent of digital television (DTV)) different uncompressed data rates and formats. Since the cost of video server storage is significant, understanding the time-dependent requirements of server storage capacity is important for system-level planning. A good understanding helps avoid wasteful provisioning of storage capacity without sacrificing operational flexibility. This paper presents a model that should be useful for planning or analyzing capacity requirements of video servers. Implications of the model for systems handling primarily long-form materials, such as near-video-on-demand (NVOD) applications will be examined.