Scheduling algorithms for video multiplexers in surveillance systems

In a multi-channel CCTV Digital Video Recording (DVR) system, a video multiplexer running switching mode allows video signals from multiple CCTV security cameras to be combined and recorded on a recording device that has only one video input. A CCTV camera can capture 30 full-size raw frames per second. In the switching mode, only a subset of raw frames can be recorded. Scheduling which channel to be recorded at which time instant is an important concern for security and surveillance. It is expected that the recorded frames from the same channel should have equal temporal distance between any two successive ones. Otherwise, there is jitter. An optimal schedule should minimize the amount of jitter. In this work, we refine the formulation of the scheduling problem. Two improved algorithms are proposed. One obtains significant improvement over a previous work and the other takes lower time complexity.