CCTV, why and how much?
To answer questions asked by our readers concerning CCTV, we are writing this article to help you think about your purchases of video surveillance.
First of all, some basic principles to be better equipped.
A - The camera watches and broadcasts what is happening in its field of vision (the scene). This field of vision varies depending on the lens type, such as fixed or variable focal length, zoom, wide angle, etc.
B - This scene is captured by the CCD or the CMOS and then sent to the camera's embedded software. This software will make at least three simultaneous video streams (1 Stream and several Sub streams).
C - These streams go to the NVR (Network Video Recorder). The mainstream, usually the heaviest, permits only the direct view. The sub-streams are intended for hard disk recording, remote viewing or other needs.
D - The bigger the hard drive, the more data you store. The higher the Substream resolution, the more accurate it is, but it takes up more space on the hard disk and reduces the retention data period.
E - The most commonly used CMOS sensors are two megapixels, rendering at 1920 x 1080 or full HD. Therefore, calculate 50 MP/sec or 180GB/H and 4To for 22 hours. The mainstream is definitively not for recording.
With these five fundamentals, you can discern the practical options for your needs.
The megapixels are always the argument to justify the price. However, you only see this resolution on the screen. If you are not in front of it, or it is too small, you do not need this quality. Of course, the recording is proportional to the original size, or if specific automatic systems need precision, you can opt for these significant definitions. But for standard surveillance, you just saved 25% of the price by limiting it to 2MP.
Famous brands influence up to more than 20% of the price. On the one hand, they are often top of the range, but the real asset remains the follow-up and the guarantee. Balance the real need against potential future developments. Simple hardware with eight years of obsolescence may be enough.
Streams are essential if we want to watch our cameras on smartphones or computers; usually, three are enough. However, if you want to install a video analytics system or other specific systems, you will need particular Streams with the possibility to modify them. You can find these options with only recognized brands.
The NVR is the device where everything happens and everything is streamed. Some are proprietary and only work with their brand. Others are freer and let you choose to add cameras from different brands. Usually, it is always better to choose ONVIF products, the standard communication standard between IP video devices.
Finally, PoE (Power over Ethernet) allows power to be sent to the cameras directly via the RJ45 cable. The NVR can include this option, but it is preferable to go through switches so that you don't have to pull threads everywhere.
There you are, you are almost professional, and you will know how to answer a simple question. Do you need an axe to cut a sheet of paper?
SDS works with three brands. A standard and inexpensive installation (small shops, villas, etc.), a medium (hotels, manufactures and SMEs) and PANASONIC for industrial or demanding deployments (embassies, institutions, sensitive sites, etc.).