I.P.CCTV
I.P., or internet protocol, CCTV has been around for some years now and, although it is growing its share of the market, it is not replacing analogue CCTV at anything like the rate that many industry pundits have been predicting.
With I.P. CCTV, each camera is an I.P. addressable device with its own processor and decoder. The digital signals from the cameras are compressed and are sent along normal structured cabling LANS or WANs to the point of recording, which may be a NAS box, video server or network video recorder. Live pictures from the cameras, or recorded images from the recorder, may be viewed from any connected PC workstation equipped with the viewing software and having the appropriate viewing rights.
One advantage of I.P. is that frequently no new cabling network is required to install a CCTV system, provided there is the capacity on the LAN infrastructure to add the new devices. Another major advantage is the image definition possible from the latest generation megapixel cameras. Frequently just one megapixel camera can be used to replace several analogue cameras and, as an example, one camera can cover four lanes of a petrol forecourt and collect images in number plate detail, which would otherwise require an analogue camera per lane.
There are still some potential drawbacks with I.P. For example the cameras are generally more expensive than analogue, and their low light performance is often not as good. But the main disadvantage for many applications is that video files, even when compressed, do use a lot of LAN bandwidth and storage and, as the image file sizes increase with the advent of megapixel, this remains a serious issue for many applications.
I.P. will continue to grow market share, and there are a number of potential remedies to the bandwidth problem:
- Networks are now available with greater bandwidths to handle the increased traffic from high definition CCTV.
- The cost of large-scale digital storage continues to tumble.
- Improved video compression techniques are being developed to reduce the size of video files still further. At the time of writing, H.264 is the latest.
- Cameras are being developed with large amounts of on-board buffer storage so LAN traffic is confined to overnight file transfer or alarm-activated events only.
KSS can advise as to whether a completely IP solution is appropriate, but in many cases we will recommend a hybrid solution. This will be achieved by using a segregated cabling system to connect the cameras, (I.P. or analogue), to a digital recorder. The recorder is then networked, so connected cameras, in live or recorded view, can still be accessed from any connected PC, but the only bandwidth consumed is a single stream of video when cameras are being viewed. The constant high-traffic communication between cameras and recorder is independent of the LAN.
