Installation and Operation Manual
FSM-IP NVR
4
P/N 06-521 (Rev. 3)
Revision Date: June, 2019
3.0 Bandwidth and Storage Calculations
For optimal allocation of bandwidth, FSM IP supports separate networks for video traffic in the form of 2
Network Interface Cards (NICs). Bandwidth of a particular network is a limited resource and overloading
the network may result in dramatic decrease of data throughput and overall performance. This overload
would result in dropped video frames and a sluggish response from the video management software.
Bandwidth planning is extremely important so that you do not overload your network with video data
traffic. Before getting to actual calculations for peek bandwidth usage, we need to discuss the tools available
to help control how much bandwidth each camera will be using. Several factors can affect the bandwidth
needed to transport the video.
Among those are:
1.
Number of channels
2.
Image quality
3.
Frame rate
3.1 Number of Channels
Although the total number of channels in the system is the result of the installation requirements, correct
allocation of the resources will be necessary for larger channel counts. Concentrating all the traffic of a multi
server job over one network may result in severe performance deterioration. Therefore, care should be
taken when multi NVR installations are considered with total channel counts exceeding 32. In such cases,
each NVR should be configured to support independent subnets that handle its respective cameras.
3.2 Image Quality
The higher the image quality, the larger the frame size. Each Fike Video Analytics IP camera provides
adjustable image quality. The image quality will have a large impact on the average camera frame’s size. This
setting is accessible through the web manager on each camera under the operator context (see IP Camera
Operations Manual). Valid image quality values are 25% to 100%, where 100% will produce the largest and
highest quality images. Due to the nature of MJPEG compression, the gains from increasing compression will
be dependent upon image content. The more detailed the image content, the less compressible the image
becomes. An example frame at an image quality of 100% compresses to 110KB, at 80% it can be compressed
to 40K, and at 25% the same image was compressed to 12K. The cameras default image quality is 80%. On
average a single frame at 80% quality will be around 60K. To change the image quality, see the Fike Video
Analytics IP Camera Operations Manual.
3.3 Frame Rate
As more frames are transmitted, more bandwidth will be required. The FSM‐IP NVR will open and maintain a
connection to each camera so it can receive frames and status information. The rate at which a Fike Video
Analytics IP camera is feeding frames is configurable and varies based on activity in the view of the camera.
The server configuration provides two rates: for active and inactive state. The inactive state is when no
motion is present within the cameras field of view. The active state is when motion is visible in the field of
view or the camera is in an alarm state. The default state is 5 Frames Per Second (fps) for active and 0.5 fps
for inactive states. This design conserves bandwidth by only streaming frames to the server when there has
been a significant change to the image.
