Traffic management schemes for constant quality video on demand

摘要

This dissertation studies traffic management schemes suitable for supporting constant-quality video on demand (VoD). Throughout this dissertation we assume asynchronous transfer mode (ATM) for the underlying communication network and variable-bit-rate encoding for the prerecorded videos. Five metrics that capture different aspects of system performance are used to analyze seven constant-quality traffic management schemes. We have developed two of these schemes, constant-rate transmission and transport (CRTT) and piecewise constant rate transmission and transport (PCRTT). CRTT transmits and transports a video's cells at a single constant rate. PCRTT transmits and transports a video's cells at different constant rates over a number of time intervals. The remaining five schemes are taken from the literature. Our analysis uses a variety of MPEG encoded videos to assess performance of each scheme. Based on our results we characterize the performance of the traffic management schemes with respect to the five metrics. We draw three major conclusions from this work. First there is no "best" constant-quality traffic management scheme; each scheme has performance strengths and weaknesses that must be assessed based on the intended VoD service to be supported. Second, our five performance metrics provide a convenient set of system descriptors. Third, the delivery of VBR MPEG video for constant-quality VoD does not mandate the use of VBR transport in the ATM network.