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The transfer of prerecorded, compressed video requires multimedia services to support large fluctuations 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 fixed rates, simplifying the allocation of resources in video servers and the communication network. Given a fixed client-side prefetch buffer several bandwidth smoothing algorithms have been introduced that are provably optimal under certain constraints. This paper presents a collection of metrics for comparing these smoothing algorithms and evaluating their cost-performance trade-offs. 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 buffer sizes, we investigate the …