Today's users of video surveillance systems have a variety of choices related to how those systems will operate, and these range from traditional systems where a camera records to a DVR to new systems where video alerts are sent to cell phones and even to professional services that allow trained monitoring staff to remotely access video streams. Each has its own benefits and drawbacks, but the general trend has been moving toward remote video guarding for commercial facilities.
The record-and-review model
Most if not all video surveillance systems use some method of recording the video for later playback and review. This is primarily a "forensic" tool as it only allows the user to see what happened after the fact. In spite of this, it is still the most common way that video surveillance systems are used.
The benefit is that the user can go back in time to see an event that occurred. Perhaps it was an act of vandalism such as the painting of graffiti on a wall or a loss of some property as a result of someone climbing over a fence in an area where goods are stored. When viewing the recorded video, the hope is that the person committing the crime or the persons involved in an incident can be identified.
The drawback to using only this approach to video surveillance is that it is indeed "after the fact". Even if the suspects can be identified via the recorded video, it may be impossible to find them. Also, at that point, the damage is already done. This is a reactive approach.
One of the primary considerations when recording video is where to store it and how far back in time you may need to go to review the video. Also of concern is the quality of the recording. If recording is done at a very low frame rate and/or resolution, the quality of the video may be insufficient for identification purposes. The higher the frame rate and resolution, the more storage is required. Another consideration is that if the video is stored at a single central location such as a DVR in the security office, there is now a single point of failure. If that unit stops operating, all recording ceases. If someone intentionally damages or removes the recording device, all video is lost.
Live, on-site monitoring of cameras
Some facilities will provide a live matrix view of all of the cameras on a screen of some sort and they will position someone to monitor those cameras in real time. The goal is that the person monitoring will see any threat as it occurs and be able to respond.
The drawbacks to this approach are high cost and low reliability. There is an often quoted study from Sandia National Laboratories which says that after viewing surveillance cameras for just 20 minutes, the attention of person responsible for the monitoring is significantly diminished. This coupled with the high cost of having someone viewing the cameras on a 24/7 basis makes this approach less than ideal. Most small- to mid-size businesses cannot afford to have their own "real time" video monitoring staff.
Remote video monitoring
This approach allows the facility to be monitored during any given period of time from a remote location. To do this, video is streamed over the Internet or via some other broadband communication method to a location remote from the protected facility itself.
This does not mean that the remote monitoring site or person is simply doing what an onsite person would. To do so would introduce the same issues as having someone perform on-site live monitoring and at the same time create an additional problem related to the large amount of video data that would need to be transferred to the remote location, typically via the internet.
Self-monitoring of video alerts
Some of the video surveillance systems available today have the ability to be programmed to send an email or some other type of notification when some event occurs such as a person entering a prohibited area. Users may think that by having these event notifications sent directly to them, they can be proactive and save the cost of having someone monitor the cameras for them. There are even apps for smart phones that allow someone to monitor their own video surveillance systems. On the surface, this can appear to be a cost-effective solution to turning a video surveillance system into a proactive security tool.