Eecient Transport of Stored Video Using Stream Scheduling and Window-based Traac Envelops

We present eecient scheduling schemes for transporting MPEG-compressed video sources with stringent, deterministic quality-of-service (QoS) requirements. These schemes are used with VBR-coded and archived videos that are transported using a CBR service. A video source is characterized by a time-varying traac envelop, which constitutes an upper bound on the actual bit rate. To provide a relatively tight bound, window-based envelops are used in which the bound is based on xed-length segments of the movie. Using such envelops, we show that video streams can be appropriately scheduled for transmission over the network so that the allocated bandwidth per stream is signiicantly less than the source peak rate (in some cases, 85% reduction in the source peak rate was achieved). This bandwidth gain is obtained via statistical multiplexing, but without sacriicing the stringency and deterministic nature of the QoS. Online procedures for bandwidth computation and admission control under the examined scheduling schemes are introduced, and numerical results are used to demonstrate and compare their performance.