The video recorder for video surveillance, which is part of the security complex, is a key element of an extensive network of analog, digital or hybrid equipment. Video cameras, as well as hard drives and other samples of network equipment are connected to it. It is important to figure out for what purposes it is acquired and what tasks it solves. This takes into account the capabilities of the device, which will be useful in the future.
Principle of operation
The video surveillance recorder works according to the following scheme:
- The video signal goes to the recording matrix.
- It is redirected to the digital processor and goes through a processing cycle there according to the specified algorithm.
- The processed information is stored on a physical medium built into the system.
As the latter, a hard disk, memory card or flash drive is used.
The matrix reproduces the transmitted image with high quality, regardless of weather conditions, light level and time of day. After its processing in the processor, a clear contrast signal is obtained, in which all distortions are eliminated. The finished video is saved on a memory card or flash drive as files. The efficiency of the video surveillance recorder and its functionality depend on the volume of the physical medium.
In general, the device operation algorithm consists of the following sequence of operations:
- Getting the original video image.
- Processing and compression of prepared files.
- Saving them on the media of the selected type.
The listed steps are typical for all types of video recorders for video cameras.
Varieties of DVRs
Known models of surveillance video recorders are divided into the following types:
- analog;
- network recorders;
- with a hard drive.
The first ones are designed to work with analog cameras and allow you to process the signal for its subsequent transmission over the selected channel. Network or IP registrars process information in digital form and need to lay special communication lines ("twisted pair" type).
Recorders with a hard disk, unlike devices with removable drives (cards and flash drives), are capable of storing large amounts of data.
Additional features of DVRs and criteria for their selection
Recorder options for video cameras include:
- improving the resolution and increasing the speed of recording information;
- increasing the volume of stored data;
- the ability to increase the number of video channels in order to exclude inaccessible zones.
The first of these possibilities is in demand when redevelopment or modernization of the serviced facility is expected. When choosing a camera recorder suitable for the stated purposes, one should be guided by the listed possibilities, but at the same time observe the measure. When choosing a device with the maximum number of video channels and cameras, you need to be sure that all of them will definitely be involved. You should not chase high resolution either, since for indicators over 3 MP, for example, expensive equipment and significant amounts of memory will be required. In most cases, it is more advisable to correctly distribute cameras in the surveillance area.
It is recommended to choose recorders that support 1 to 2 MP resolution.It is quite enough for organizing video surveillance of personnel actions and identification of human contours. It is also advisable to familiarize yourself with the technical indicators for the recording speed, which should not be lower than 25 frames per second per camera. When operating video recorders for video surveillance for 4 cameras, this figure should be 100 frames per second.
Features of connection and settings
For the correct operation of the video recorder for cameras, excluding its overheating, the devices are placed in areas with effective ventilation. If they have the PoE function, you do not need to observe the polarity of the power supply. In samples where it is absent, the correctness of the connection is necessarily controlled. During installation, the connectors and sockets are installed in separate junction boxes, which protect their connection terminals from oxidation.
Customization
At the end of the installation work, the installed and connected equipment is adjusted. Procedure:
- On each module, the exact time and date are set for binding to recorded events.
- Formatting of built-in and external storage devices is in progress.
- The parameters of the cameras' review are configured - the angles of their tilt and rotation are set.
- In addition, you need to tune in to the desired video recording mode using special applications.
At the final stage, the function of remote access of the video recorder for video surveillance systems to the serviced cameras is activated. For these purposes, cloud services are most often used.
The best models of DVRs
When servicing video cameras, the 720-1080P format is used, and to obtain a high-quality image, it provides six levels of recording. A typical H.265 / H.264 compression algorithm is used to store information. The archive built into the system is designed for 6 TB of information located on the hard disk.
