A new technique for transmission of pre-encoded MPEG VBR video using CBR service

This paper presents the system issues involved with the transmission of pre-encoded variable bit rate (VBR) MPEG video using the constant bit rate (CBR) service. Conventional wisdom suggests that lossless delivery of VBR video using the CBR service requires bandwidth to be reserved at the peak rate resulting in low bandwidth utilization. We calculate the minimum rate at which bandwidth must be reserved on a network in order to provide continuous playback of an MPEG encoded video bitstream. Simulation results using the frame size traces from several pre-encoded MPEG bitstreams and several buffer sizes demonstrate that this "minimum reservation rate" is much lower than the peak rate when a modest playback buffer size is used, resulting in much higher bandwidth utilization. Procedures for performing connection setup and lossless realtime video playback between the video server and the client are outlined. Methods for incorporating VCR-like features such as "pause" and "fast forward/reverse" for video-on-demand (VoD) applications are presented.