A Novel Video-On-Demand Storage Architecture for Supporting Constant Frame Rate with Variable Bit Rate Retrieval

One of the quality of service (QOS) factors in video-on-demand (VOD) applications is to provide high resolution quality to end users. One way to achieve this is to provide a constant display frame rate (e.g., 30 frames/sec) at the display station. However, due to the nature of video files and compression technique applied, video frame sizes vary significantly from frame to frame. Therefore, although the display frame rate is fixed, data retrieval is a variable bit rate process. Conventional VOD storage servers assume a peak rate retrieval of video files. Therefore, the number of concurrent requests to the VOD server cannot be maximized. In this paper, we consider a VOD storage server which can support a fixed frame rate at the display and at the same time, variable bit rates retrieval of compressed video files. We describe 1) video files layout strategy, 2) request scheduling algorithm, 3) buffering issues and, 4) various VCR features support such that the number of conclurent requests can be maximized.