Hybrid mode (AHD+IP)
The number of cameras supported by the recorder when operating in hybrid mode — that is, when using traditional (AHD) and network IP cameras at the same time. For details about hybrid recorders, see "Type". And in this paragraph, the first number indicates the number of conventional cameras, the second — IP devices: for example, the entry "4 + 2" indicates that this model can simultaneously receive a signal from 4 conventional and 2 IP cameras.
Also note that some hybrid recorders allow different ratios between the number of cameras of different types (with the same total number of cameras). For example, a 12-channel model may have 6+6, 8+4, and 10+2 hybrid modes. In such cases, this paragraph takes into account the mode with the largest number of AHD cameras; for the model described in our example, “10+2” will be written in this paragraph.
It is also worth mentioning that when working only with IP cameras, the hybrid recorder can support a greater number of video channels than in hybrid mode — for example, in the “2 + 8” format model, the number of supported only network cameras can reach 16. This information is specified in "IP Only".
IP only
The number of cameras (video channels) supported by the hybrid recorder (see "Type") when working with IP cameras only.
Most often, this number corresponds to the total number of channels available in hybrid mode (when IP cameras are combined with traditional, so-called AHD cameras). For example, for a DVR with 8+2 hybrid mode (10 in total), the number of cameras in IP only mode is also usually 10. However, there are exceptions: some models in pure network mode are able to work with more cameras than in hybrid. For example, the same hybrid format "8 + 2" can be combined with support for 16 or even 24 network cameras at the same time.
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.
Resolution (all channels)
The highest resolution in which the recorder can record video when a signal is received from all channels simultaneously. If cameras are not connected to some channels, the recording resolution may be higher (see “Maximum Resolution”).
Higher resolution has a positive effect on detail, but takes up more space and requires more computing power for processing, which accordingly affects the price of the registrar.
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).
Max. resolution (IP)
The maximum supported resolution of IP cameras with which the NVR is technically capable of working (primarily recording). With rare exceptions, devices record in maximum resolution from all connected IP cameras. However, the limiting factor here is bandwidth (see the relevant paragraph) – depending on the shooting conditions, it may not be enough.
High resolution allows you to get a more detailed image in which fine details are better visible. On the other hand, such videos take up large amounts of disk space, and their support significantly affects the cost of the device.
Max. resolution (analog)
The maximum video recording resolution supported by the recorder when operating in analog mode. If this figure is higher than the resolution when recording from all channels at once (see above), then the recorder is capable of recording at maximum resolution only if some of the video channels are not occupied by cameras. In different models, the required number of free channels may also be different. However, there are instances in which the maximum resolution is achievable even at full channel load.
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.
