TVI (Transport Video Interface) is the latest, and in our opinion the best, HD video over analogue CCTV system. It is capable of giving the same resolution (1080P) as the older HD-SDI (Serial Digital Interface) and HD-CVI (Composite Video Interface). All three systems use pre-processing of the video signal at the camera prior to transmission via analogue cable.
HD-SDI is still available (May 2015), but we predict that as soon as residual stocks are depleted it will not be available for new installations. There are two major drawbacks with HD-SDI - firstly, it is relatively expensive and secondly, although it is advertised as being compatible with existing analogue cabling, it requires that the analogue cabling is in top condition. Standard analogue systems are relatively forgiving as regards cabling but SDI is not. HD-TVI is not overly "picky" about the cabling quality, although it is always best practice to use the best quality cable and connectors.
Our preferred manufacturer is Hikvision who are renowned for their quality and technical expertise.
HD-TVI technology was developed by Techpoint and is an open-source technology and as such has been adopted by the major manufacturers of CCTV equipment such as Hikvision and Dahua.
The advantages of HD-TVI are as follows:
Compatibility - HD-TVI is compatible with existing D1/960H cameras and can also use the existing analogue cabling. TVI cameras from one manufacturer are generally compatible with TVI recorders from a different manufacturer.
Hikvision TVI Cameras can connect to standard analogue (D1/960H), but will only display at D1/960H resolution.
Hikvision TVI DVRs can connect 1 or 2 (model dependent) IP cameras. The cameras must have the Hikvision protocol available - if in doubt use Hikvision IP cameras. The display/record resolution will be either 720p or 1080p (model dependent).
Resolution - HD-TVI can record and playback at up to 1080P - see "CCTV Resolutions Explained" for information on CCTV resolutions.
This revolutionary technology allows users to send uncompressed, high-resolution video over coaxial cable. The Turbo HD product family comprises full HD cameras and DVRs that offer seamless compatibility with multiple video formats, from standard definition analogue to HD-TVI to megapixel IP. Other benefits of HD-TVI include absence of video delay in live viewing, bi-directional signalling, and highly efficient storage, adding up to an incredible breakthrough in the evolution of analogue transmission.
The main problem with HD-CVI is that it is only made by one manufacturer with the result that it is rather expensive limited in compatibility. It is also not backward compatible with existing analogue systems. It should also be noted that the same manufacturer has now moved into HD-TVI. So it would seem that HD-CVI is effectively dead.
We should also mention another emerging technology - HD-AHD (Analogue High Definition). Having tested a couple of AHD systems, we feel that it doesn't offer any significant advantages over TVI.