NVR is the future for enterprise systems
First came the camera and monitor, closely followed by the video cassette recorder, recording one video stream to a three-hour tape at 25 frames per second and often triggered by an input device.
Technology then brought us the multiplexer, which allowed several streams of video to be recorded onto the same tape and separated out into discrete, viewable streams on replay and the time-lapse VCR.
The development of video compression algorithms, the increase in computer processing speeds and a rapid reduction in data storage costs then gave rise to the DVR. This you could consider as being the functionality of a multiplexer together with a computer disk for storage in place of tape, all housed in the same box together with some additional ports for connectivity.
The DVR provides a convenient, if limited, replacement for the multiplexer-VCR combination and provides non-linear access to recorded material usually selected by camera ID, time and date. The consistency of the quality of recorded material will in general be higher than that obtained with analog tape, although the actual quality achieved may or may not be better, depending on the compression algorithm and individual configuration.
The network video recorder heralds the arrival of the next natural point in the development of recording technology.
It is important to differentiate between DVRs and NVRs, as both are often termed digital. A DVR digitally compresses analog video feeds and stores them on a hard-drive, the term digital referring to the compression and storage technology, not the transmitted video images. The DVR therefore has to be located near the analog feeds. In contrast an NVR stores digital images directly from the IP network. Therefore, the most obvious difference between the DVR and NVR is that whereas the DVR records from analog streams provided from analog cameras, the NVR records video streams that have already been encoded at the cameras. Thus you find no video connectors anywhere on a NVR; its input and output is IP data comprising compressed and encoded video. This will typically be in MPEG-4 format, which has enjoyed widespread adoption in the CCTV industry as the current compression technology of choice, due largely to its efficiency.
The huge advantage of architecture based on NVRs is that they can be located anywhere on a network. In use, their location is transparent to an operator - he or she simply calls up the recorded video stream to be viewed and, provided that they have the necessary authorization, there it is. NVRs record and replay simultaneously, and recordings on any one machine can be remotely viewed by a number of authorized operators spread across the network simultaneously, all totally independently and without affecting each other.
Many tools are already available to assist the operator identify and replay events of interest from a recording. Systems can analyze movement in a scene and on command from an operator display thumbnails on the screen that represent frames from recordings containing the specified movement. Clicking on one of the thumbnails then replays that section of video. The system can search 24 hours of recorded video and display these thumbnails in just a few seconds. Changing the search variables allows the operator to sift through vast quantities of recorded material quickly and efficiently. Analytics software then searches for the events requested, saving the frustrating and time-consuming task of manually searching through hours of video and freeing the operator to concentrate on more specialized and immediate tasks. These are not just features to benefit the user but they also help to reduce the overall demand on the network. It can be expected that huge productivity improvements will result from using analytics software during the searching of recorded material in post-event analysis, and for which the NVR is the key.
Oliver Vellacott is CEO of IndigoVision Inc.,