Video channels
The number of video channels that the set's recorder is capable of simultaneously processing. In fact, this is the number of cameras that the device can simultaneously work with; it is technically possible to connect more cameras, but this will require additional equipment — such as quadrators.
The choice for this parameter depends on how extensive and extensive the observation system is planned to be built. At the same time, it should be noted that modern technologies allow combining several registrars into a system with a single control; therefore, for numerous cameras, it is sometimes easier to purchase several relatively modest kits than one multi-channel one.
Max. capacity
The largest storage capacity with which the recorder is able to work normally.
The more capacious the drive, the higher the processing power of the system in which it is used should be. Therefore, any modern registrar has limitations on disk capacity. However, even in the most modest models, this figure is about 2 TB, in most cases this is quite enough to work with the capabilities provided in this particular registrar.
Pointed cameras
The number of pointed cameras that are standardly supplied with the video surveillance kit. For more information about this variety, see "Type of cameras", here we note that the total number of cameras in the set (both pointed and dome cameras), usually, is less than the number of video channels (see above). This allows you to buy additional cameras if necessary, choosing them at your discretion.
Matrix size
The physical size of the sensor in the pointed cameras is diagonally, in inches (fractions of an inch).
The larger the sensor, the less prone it is to noise, the better image quality it can provide, and the better it is suited to low light conditions. This is due to the fact that each individual pixel gets more light, because. on a large matrix and individual dots are larger. On the other hand, large matrices are more expensive.
Horizontal viewing angle
The viewing angle of the directional cameras supplied as standard is horizontal.
Wide viewing angles allow you to cover a large area; this is especially important given that directional cameras are often made stationary. On the other hand, all other things being equal, a larger viewing angle will mean a lower degree of magnification - objects will look smaller, detail will be worse. Therefore, when choosing according to this parameter, you should proceed from what is more important - a wide field of view or “range”.
PTZ (managed)
Support of the complete registrar of controllable
PTZ cameras.
Lenses in such cameras are able to rotate from side to side and up and down, as well as change the degree of image magnification (however, not optics, but digital zoom may be responsible for the latter). Thus, the area covered is significantly expanded (although part of it is constantly behind the scenes), and the operator can direct the camera to the point of interest to him. In addition, the movement of cameras can be automated — for example, programmed to constantly turn from side to side, to aim at the door when the lock is triggered, etc.
Support by the PTZ recorder is mandatory for the normal operation of cameras with this function. At the same time, the controlled cameras themselves in this case may be included in the kit, but this is not necessary, so their presence should be specified separately.
BNC video input
The number of
BNC video inputs provided in the design of the complete registrar.
BNC is a standard coaxial cable interface used to transmit analogue video signal in video surveillance systems; accordingly, it is found only in analogue and hybrid sets (see "Type"). The number of BNC connectors usually corresponds to the number of analogue video channels supported by the DVR.
Recording resolution
The maximum frame resolution in which the complete recorder can record video if all video channels are involved in operation. In fact, we are talking about the highest resolution in maximum load mode; if some channels are idle, some models allow higher resolutions. However, it is customary to indicate this parameter in the specifications - it most accurately characterizes the capabilities of the device.
As for the resolution itself, the higher it is, the more detailed the image is; on the other hand, such video requires significant processing power and capacious storage drives, which affects the final cost of the equipment.
Popular maximum frame resolutions in which modern recorders record:
HD (720),
Full HD (1080),
Quad HD,
Ultra HD (4K).
Frame rate
The highest frame rate at which the complete recorder can record at full load when all video channels are used. In other words, this is the guaranteed maximum frame rate that can be achieved at any load level (with some channels idle, the number of frames per second may be higher, but not necessarily).
The higher the frame rate, the better fast movement will be captured, the less blurry objects in such scenes will turn out. On the other hand, this indicator directly affects the cost of equipment and the amount of memory occupied by the footage. For video surveillance systems, an indicator of 24 fps is currently considered the minimum necessary, 50 – 60 fps is not bad, and in the most advanced registrars this number can reach 120 fps.
