Comparison Hikvision HiWatch DS-H208Q vs Dahua DH-NVR2116-S2

The type primarily determines the type of cameras with which the recorder is compatible.

— Analog DVR. Devices of this type can only work with traditional surveillance cameras that output video in analogue format (usually via a BNC interface, see below). Despite the emergence of more advanced options, such cameras are still very popular due to their simplicity, low cost and reliability of video transmission. The recorder itself may have a LAN network interface and work as a network device, but it is not compatible with IP cameras.

— Digital NVR. NVR type recorders are designed to work with IP cameras connected via a local computer network. These cameras are more advanced than traditional analog cameras and support more advanced features. The main disadvantage of NVR is the rather high load on network equipment when transmitting streaming video; this can lead to interference and failures, especially when there is a large flow of other traffic on the network.

— Hybrid HVR (HDVR). Hybrid devices that combine the capabilities of DVR and NVR and can work with both analog and IP cameras. This expands the possibilities for building surveillance networks, allowing you to combine the advantages of both types of cameras and mutually compensate for the shortcomings. However, such equipment is not cheap.

Possibilities for connecting cameras available in the registrar.

For analogue DVRs and digital NVRs (see "Type") in this case, everything is simple: the number of video channels corresponds to the largest number of incoming video signals that can be connected to the device. Such a signal can come both from a camera and from an intermediate device — for example, a quad that combines a picture from 4 cameras. But in hybrid HVRs, the meaning of this paragraph is more specific. For these recorders, this specifies the maximum number of inputs that the device can handle in AHD only mode (i.e., analogue cameras only, no IP cameras). Data on hybrid mode (AHD+IP), as well as for using only IP cameras, are given separately for such recorders (see below).

Numerous channels ( 32 channels, 64 channels and even 128 channels) allows you to create an extensive video surveillance system based on the registrar without using additional equipment (for example, the same quads). On the other hand, this characteristic significantly affects the price, and for living conditions, registrars for 4, 8 or 16 cameras are quite enough.

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".

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.

The number of BNC inputs 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. In registrars, inputs with such connectors are used to connect analogue cameras. The more connectors, the more analogue cameras can be connected directly to the registrar at the same time; and in DVR devices (see "Type"), the number of BNC inputs corresponds to the number of 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.

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.

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.

Support of the registrar of the ONVIF standard.

This standard describes the protocols for the interaction of various components of a video surveillance system; a registrar that supports it will be fully compatible with other ONVIF equipment, regardless of manufacturer.