CCTV SURVEILLANCE 101: Video motion detection recording
All digital recording systems use video motion detection for recordings. Video management software (VMS) will analyze consecutive frames of the video for changes in pixels and then will write the section of video to disk.

Installing outdoor cameras

This process is very CPU intensive and is one of the limiting factors with respect to the number of cameras that can be recorded on a single computer. The other major factor that limits the number of cameras per computer is the maximum bandwidth of the video feeds combined, which can create bottlenecks at the network adaptor or when writing to disk and will result in missing footage or jittery recorded footage.VMS manufacturers have developed some tricks to minimize this impact on the CPU in order to record more cameras or higher resolution cameras to disk. In order to lighten the load on the CPU, not every frame of video is analysed, most good VMS systems will have a setting where you can adjust the interval between the frames that are analysed for pixel change. This can greatly reduce the work of the CPU, but if the interval between the frames scanned is too great, critical information could be missed such as sleight-of-hand in a casino.Pre- and post-video buffering is a technique that is used to keep a few seconds of video prior to the detection of pixel change. Once pixel change is detected then this video is also written to disk. This can help compensate for video motion detection that is not very sensitive and may miss some of the event, for example, when there is only a recording of someone when they are already in the middle of the room, by using pre-buffering you could also include the few seconds before.To get this and more, enlist in this elite training of CCTV surveillance: