HD-CVI is a standard patented by Dahua Technology company.
HD-CVI is a proprietary standard developed by Dahua Technology. It offers two resolutions: HD (1280 x 720) and Full HD (1920 x 1080).
HD – 1280 x 720 px
Full HD – 1920 x 1080 px
4 Mpx – 2560 x 1440 px
8 Mpx 4K UHD – 3840 x 2160 px
HD-CVI transmits video, audio and control signal via a single coaxial cable - Fig. 1.
1 - HD video signal
2 - Bidirectional data transmission
3 - Audio signal
The system must be installed in star topology similar to the one used in analogue systems. The camera connects to the recorder in point-to-point mode.
Signal transmission distance specified by the manufacturer is up to 500 m - using RG-59 coaxial cables. The tests showed that at 1080p, the distance is 400 m without any deterioration to the image quality. At 720p, the distance increases to 500 m. The distance can be further extended with higher quality cables. The signal can also be transmitted via a twisted pair. The maximum distance depends on the video balun used (in most tested models it is approx. 150 m).
HD-CVI monitoring is an alternative for legacy analogue system users. Without replacing the cables, it offers high quality Full HD videos.
Fig. 2. Screenshot from HD-CVI camera at 1080p
The following should be considered when selecting the recorder: supported resolutions and systems (the selected models are compatible with three standards: HD-CVI, IP and analogue, i.e. ‘three-mode recorders’) and the number of frames assignable to each channel. For recorders supporting analogue cameras, user can move to a HD-CVI system without the need to replace all the cameras at once.
Detailed parameters of the standard can be found in the article: