PeriodPatch: an efficient stream schedule for Video-On-Demand

Stream schedule used in Video-On-Demand (VOD) system can largely enhance system service ability by eliminating the service latency. In this paper, we propose a novel stream schedule called PeriodPatch. On the basis of Patching, we introduce a PERIOD rule that the movie time in the main stream should be a linear function of system time, so that multicast streams are created regularly and fewer multicast streams are needed for the True Video-On-Demand (TVOD) service. Furthermore, PeriodPatch schedule ensures that the system can provide Near Video-On-Demand (NVOD) service with the predictive and acceptable latency to client if resources are exhausted out. To assess the benefit of our schedule, we perform simulation to compare the performance of PeriodPatch with that of FIFO and Patching schedule. Results show that PeriodPatch is more efficient than other schedules, with respect to both system resources required for TVOD service and average client waiting time (service latency). In our case, PeriodPatch only uses 38% streams of FIFO or 50% of Patching schedule to provide the same TVOD service. Results also show that PeriodPatch is not a buffer-related schedule unlike Patching and other schedules. Our simulation proves that the suitable size of client buffer can achieve better performance.