Digital-video-recorder (DVR) technology became part of business and home security systems in the early 1990s. It gradually replaced video-cassette recorders (VCR), which had been used in security cameras up to that period. The practical benefits of digital technology were immediately recognised.
Traditional VCRs could only store a few hours of video per tape. Someone had to remember to change the tape in a camera every four or five days. VCR manufacturers tried to overcome this problem by introducing time-lapse recording. Instead of 30 frames per second, the camera recorded one frame per second. This meant that some details of a security incident could be missed, or sometimes the entire event would not be recorded at all.
There were common problems associated with all manner of tape recording, whether video or audio. The tapes would break, the recording quality deteriorated as the tapes were over-recorded several times and the recording machinery mechanism could fail.
The DVR security camera offers a solution to all of these problems. The equipment is made up of two basic devices: a security camera and the recorder – the DVR. Signals from the security camera are transmitted to the DVR system device. This converts the signal into a digital format and the file is saved on computer hard drive.
DVR technology has overwhelming advantages. It is more reliable and can store more data and can record over months and years. As digital systems are automated, they do not rely on someone remembering to change a tape when it runs out. The image quality produced by DVR security cameras is superior to analogue images. Megapixel technologies and progressive scans have improved the image quality and provide a better resolution than analogue cameras. The digital technology can also protect the data.
All data in DVR systems can be accessed quickly by multiple users. These users are able to view it remotely or locally. Security personnel and corporate management can recall video clips immediately without rewinding or forwarding a tape. It is also important that third parties, such as a security company or the police, can gain access to the video and the DVR system provides such access.
The quality of a digital image does not deteriorate as it travels through the cable network of a surveillance system. In contrast, analogue images become degraded and weaker with increased cabling distance.
Digital systems allow surveillance personnel to manage a security event efficiently. With analogue devices, someone had to sit through hours of recorded video to find a particular incident. Often there was insufficient time to find the incident, let alone analyse it.
Digital systems have built-in intelligence and analytics in cameras and encoders to locate and examine events. Any operator can programme the system so that it responds to specified events. This, in turn, can be tied to existing alarm networks.
A DVR security camera and surveillance system is a sophisticated undertaking requiring dedicated designers, programmers and engineers, together with specialised software and hardware. The system includes sub-assemblies of devices, as well as built-in checks and balances.
Reliable DVR security-camera manufacturers are able to install a surveillance solution for business or home security systems that is compatible with existing CCTV coverage of any premises. They are able to upgrade the system to address new security problems, introduce better technology and generally adapt to the user’s requirements.
As long as the DVR security-camera system is properly designed, it will be cost effective. Different products can be added to a business or home system without expensive changes to network infrastructure.