Performance Evaluation of Smoothing Algorithms for Transmitting Prerecorded Variable-Bit-Rate Video

The transfer of prerecorded, compressed video requires multimedia services to support large uctuations in bandwidth requirements on multiple time scales. Bandwidth smoothing techniques can reduce the burstiness of a variable-bit-rate stream by prefetching data at a series of xed rates, simplifying the allocation of resources in video servers and the communication network. Given a xed client-side prefetch buuer, several bandwidth smoothing algorithms have been introduced that are provably optimal under certain constraints. This paper presents a comprehensive performance evaluation of bandwidth smoothing algorithms, based on a collection of metrics that relate directly to the server, network, and client resources necessary for the transmission, transport, and playback of prerecorded video. Due to the scarcity of available trace data, we have constructed a video capture testbed and generated a collection of twenty full-length, motion-JPEG encoded video clips. Using these video traces and a range of client buuer sizes, we investigate the interplay between the performance metrics through simulation experiments. The results highlight the unique strengths and weaknesses of each bandwidth smoothing algorithm and pinpoint promising directions for future research.