BNC video output
The number of BNC outputs provided in the design of the registrar.
BNC — connector with bayonet fixation for coaxial cable, used including for transmission of analogue video signal in professional equipment. Outputs with such connectors are designed to transmit a video signal to other components of the surveillance system — for example, monitors.
BNC outputs are found in all types of modern recorders (see above). At the same time, in DVR-type devices, their number, usually, corresponds to the number of BNC inputs, which makes it possible to switch the signal from each camera through its own output. In the NVR, most often only one connector is installed, which is intended for viewing recorded materials, and not images from cameras. The same option is also popular in HVR, although there are also models similar to DVR among them.
USB 3.2 gen1
The number of
USB 3.2 gen1 ports in the design of the registrar. This interface is used to connect various peripheral devices: USB drives for copying files or updating firmware, keyboards, mice, etc.
Specifically, USB 3.2 gen1 is the successor to USB 2.0. It supports higher data transfer (up to 4.8Gbps) and higher power supply.
Bandwidth
The maximum data stream in Mbit/s that the NVR is capable of processing when recording and displaying. The throughput parameter is specified as the maximum incoming/outgoing speed, or as the sum of incoming and outgoing streams (total throughput). It is calculated in such a way that the throughput exceeds the total flow of all IP cameras connected to the DVR, and another 25–30% is put in reserve for playing video or viewing it via network access.
Frame rate
The highest frame rate in the recorded video that the recorder can support when recording from all available channels simultaneously. If not all channels are occupied by cameras, this figure may be higher.
The minimum required for comfortable viewing is 24 fps. And in the most modern video standards, the frame rate can be much higher — 50 – 60 fps. Higher values result in better quality and smoother video that allows you to clearly see fast movement; however, such video takes up more space and requires powerful hardware, which affects the price of recorders.
Recording 25/30 fps (all channels)
The highest resolution in which the recorder can record video with a frame rate of at least 25/30 fps when a signal is received from all channels simultaneously. The parameter is specified for models that have high resolution shooting with a low frame rate (for example, 4K at 15 fps). It gives an understanding of the specific resolution at which video recording with a frame rate of 25/30 fps is achieved, at which the picture is perceived more smoothly and details in dynamic scenes are better visible (if there are moving objects in the frame).
Video compression format
Standards (codecs) used by the recorder to compress the recorded video.
This parameter is important when viewing recorded materials on another device — for example, a media centre, into which a "flash drive" with files from the recorder is inserted. For normal viewing, it is necessary that the player supports the appropriate codec — otherwise the video will be displayed with distortion or will not work at all. Technical details on various standards can be found in special sources.
Note that if you plan to view the materials on a computer, you can not pay much attention to this parameter: most modern operating systems have extensive built-in sets of codecs, and if you don’t have the right codec, you can easily find it on the Internet.
Number of SATA
The number of SATA connectors provided in the design of the registrar.
SATA is the most popular modern interface for connecting internal drives. One connector allows you to connect one hard drive (or other internal media), that is, the number of such connectors is, in fact, the largest number of separate drives that can be installed inside the recorder at the same time. Basic versions can be equipped with
one SATA connector or
two. More advanced ones have
4 SATA connectors, and already models for serious objects have much greater connectivity.
Max. total capacity
The largest total storage capacity with which the recorder is able to work correctly. By default, it is indicated only for internal media with a SATA interface (see above), however, in some models, data is also provided separately for external devices connected via eSATA.
Note that the limit on the total capacity follows from the fact that each individual port has its own limit on the capacity of the drive. In this case, the maximum capacity is distributed equally between the ports. This should be taken into account when choosing drives for the registrar: for example, in a 32 TB model with 8 SATA connectors, the limit for each connector will be 32/8 = 4 TB. This means that installing two internal 8 TB disks in such a registrar will not work, although their total capacity will be less than the maximum.
