What is a DVR?

Surely everyone in life has had cases whenin the absence of witnesses of any incident, he could not prove his rightness or innocence to what had happened. In such cases, only the DVR can be of help, it is a device for recording and processing digital video, with the possibility of its replay. These technical devices have long ceased to be a rarity in the electronics market, but many still do not know what a DVR is and why it is needed.

Types of DVRs

Although there is no universally recognized classification of DVRs for any particular criterion, some devices are still formed into separate groups:

Network Video Recorders (Network Video)Recorders) are devices for recording, storing and playing video that receive a signal directly from the IP camera and archives the data for further storage.
Hybrid Digital Video Recorders - devices for recording, storing and playing video from both analog and IP cameras.
PC-based Digital Video Recorders can work in multitasking mode due to the use of computer power.
Car DVRs (Car DigitalVideo Recorders) are used to record traffic from the car, truck, boat and other vehicles. They are also sometimes called mobile, in contrast to other stationary recorders.

However, there are other classifications. So, for example, by the number of channels for recording a signal, DVRs can be single-channel, two-channel, four-channel, six-channel and eight-channel.

DVR functions and usage area

A full-featured DVR has the following capabilities:

FullHD recording is the most high-quality recording format for the current moment (1920x1080 pixels).
GPS-receiver - an indispensable thing in emergency situations. It shows the coordinates and speed of the movement.
G-sensor - a sensor that is able to accurately determine which side was hit. The sensor data can be used in court as evidence.
IR illumination - guarantees full recording even in the dark.
Zoom - the ability of the recorder to enlarge a fragment of a video or image.

Depending on the purpose for whichthe DVR is designed, some functions of the device may be missing or realized in a lower quality (for example, the recording format can be VGA, and Zoom - only two-fold or absent at all).

So, DVRs can be used not only in machines, but also:

in video surveillance systems of private houses, office premises and various public buildings for security purposes;
in cafes, eateries, restaurants and shops formonitoring of personnel activities. Video surveillance allows, for example, to identify the cause of the discrepancy between cash amounts in cash and data from POS terminals;
at various checkpoints and in organizations equipped with security points, for the account of visitors and vehicles located on the reporting territory;
at large enterprises and in various centers, where it is necessary to control all the processes occurring simultaneously in such a large territory, etc.

Principle of operation of the DVR

The most common work of the DVR can be described as follows:

A camera designed to perform aa specific task, removes what is happening with a certain time interval, given settings, and transmits the video signal to the DVR over the cable.
The device processes the received signal taking into account the date, time and duration of the video recording.
A special codec archives or compresses the received data and stores it on the built-in memory or memory card.

Depending on the model of the DVR to itYou can connect up to 8 analog or ip-cameras simultaneously. In addition, you can connect a microphone, while the video will be superimposed and audio recording. The period of storage of video recordings on the recorder mainly depends on the amount of memory of the hard disk to which it is connected.

For acquaintance with this technical device, read also the articles: