HD CCTV (High Definition)
High Definition CCTV (HD-CCTV) is a progression from analogue standard definition CCTV (SD-CCTV).
The technology utilises the same technology as is used in broadcast HD television which gives a much enhanced image over standard resolution. It should not be confused with HD-IP-CCTV which is a Internet Protocol CCTV system.
HD-CCTV is positioned between standard definition and mega pixel IP-CCTV. The primary advantage of HD is one of cost. One can reap the advantages of high definition for only a small increase in equipment cost. Another major advantage is that the HD signal (HD-SDI) can be carried over conventional video coaxial cable (RG 59) meaning that a full re-cabling can be avoided. (With IP-CCTV all cabling must be replaced with CAT5e Network cable) HD-SDI is a standard developed for the TV industry and therefore has been tested and products (such as cameras, Digital Video Recorders (DVR’s) and distribution hardware) are being developed to be interchangeable.
As this is the zenith of non-IP (Internet Protocol) technology the products that are offered are generally feature rich and lower cost than an equivalent entry level IP system. The HD-CCTV DVR’s tend to be network friendly with features such as dual encoding for fast transmission of images over the web.
It is important to understand that HD-CCTV is viewable over the internet and some features such a image zoom-in work in the same way as IP-CCTV. It is, in fact, the DVR that is the network device and the attached cameras are network passive or “dumb”; that is they can not be addressed directly over the network. In an IP system each camera is a network device in its own right and can be controlled and configured remotely.
So what are the disadvantages of HD-CCTV if it is cheaper than IP and offers almost the same resolution?
As this technology has been developed about as far as one can go with the existing system (there is some talk of 3D HD CCTV?) it is not an investment that can be improved upon. It will be a closed system which can only be added to with the same technology. This is fine if the expectations of a user are met but based on the massive improvements in image quality in the last 5 years it is fair to assume that in 5 years the users expectations will have moved on. Another disadvantage is that all cabling has to be done using RG 59 coaxial cable (there is development of active baluns (baluns are converters of video signal to a signal that can be carried over network cable Cat5e) but they are still very expensive and untested technology) and this means that a upgrade to IP-CCTV in the future will also require a re-cabling of the whole installation.
HD-CCTV will be the right solution for some clients who know exactly what they wish to achieve with a limited budget and will not wish to upgrade the system going forward. They will achieve a significant upgrade from SD-CCTV for only a small increase in costs.
HD-CCTV offers the following advantages:
HD has the following disadvantages:
|Type||SD-CCTV (Standard Definition)||HD-CCTV (High Definition)||IP-CCTV (Internet Protocol)|
(576 TV lines)
(1080 TV lines)
|2MP (Entry standard)|
(Up to 10MP)
CAT5e (with adaptors)
CAT5e (too expensive)
|Connected to Network||DVR||DVR||DVR and all IP Cameras|
|Future Development||None||Some in short term||Ongoing and future development likely|