When implementing a video surveillance project in a residential neighborhood, several important points must be taken into account in order to successfully deploy our solution.
On this article, AirLive will be explaining the issues related to the bandwidth needed for each camera.
Each viewpoint needs to be allocated the “right” air borne space to be effectivelly transmitted from the client to the monitoring center. This is determined by calculations that must be kept in mind for this kind of developments::
According
to the compression methods, the values in the table are the exact numbers. In
this regard, it should be noted the difference between H.264 and MPEG-4, since
this pattern compresses much better than the MPEG-4. Based on these
specifications, then we have a real idea of the bandwidth required for each
camera.
Alternatively, the user can also get his own calculations by means of AirLive application that can be accessed on the following link: http://fs.airlive.com/firmware
/NVR_DiskCalculator.zip
There
are several factors that influence the calculation:
1) Resolution of
each camera
2) Frames per Second
(FPS)
3) Compression Method
Importance: if the camera supports
H.264 compression, it is recommended to use it because it is a more advanced method
for video compression. Below is a comparison chart of compression methods:
After
this first step, you have determined the actual bandwidth required and the
amount of each camera, but then another key point to be considered is the
calculation of the WiFi connection According to the mode of operation, we get a
different throughput. Here's an example (based AirMax5N)
These
statistics are essential to calculate the maximum bandwidth that is available
from a link as their distances and modes of operation. This is the calculation
to be done:
-
Number of cameras in possible link = (Throughput available x 50%) / bandwidth
needed for each camera
Example
-
Throughput of link Static Turbo mode within 1 km: 45 Mbps- Bandwidth required for each 1 Megapixel camera with 30 FPS: 4.18 mbps
-
Number of cameras in possible link = (45 x 50 mbps%) / 4.18 mbps = 5 cameras
Throughput is obtained from the above table, the required bandwidth
of each camera, through the AirLive NVR Disk
Calculator. Finally, the factor
50% is always used in the link between two
computers as a buffer space to cover events that might affect and reduce the performace
of the link (for instance weather conditions).
Now with all these values in
hand, it is possible to install an outdoor surveillance project in a more effective manner, no matter if
it is a point-to-point or a point-multipoint deployment.
