Bandwidth management
Network video products utilize bandwidth based on their configuration. Bandwidth usage depends on:
- Image resolution
- Compression ratio
- Frame rate (images per second)
- Complexity of the scene
The following technologies are among those that enable management of bandwidth consumption:
Switched networks:
By using network switching —a common networking technique today— the same physical computer and video surveillance network can be separated into two autonomous networks. Even though these networks remain physically connected, the network switch logically divides them into two virtual and independent networks.
Faster networks:
As the price of switches and routers continues to fall, Gigabyte networks become an affordable option. The trend towards faster networks increases the potential value of remote monitoring over networks.
Event driven frame rate:
a rate of up to 30/25 frames per seconds (fps) on all cameras at all times is above what is required for many applications. With the configuration capabilities and built-in intelligence of the network camera/video server, frame rates under normal conditions can be set lower, e.g. 5-6 fps, dramatically decreasing bandwidth consumption. In the event of an alarm, if motion detection is triggered, the recording frame rate speed can be automatically increased to a higher frame level.
In many cases, the camera will only send video over the network if the video is worth recording; the rest of the time, nothing is being transferred over the network.
Calculating bandwidth needs
A bandwidth calculator helps to determine the bandwidth a network video product will use, based on the image size and frame rate. It also calculates how much space a recorded image sequence would require. See AXIS Design Tool.
See also other System design considerations:
