Clare Controls IP Network Camera, User Manual, Page: 78 / 92

70 Clare Controls IP Network Camera User Guide
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Understanding camera capacity in an NVR
When setting up your NVR and cameras, you may notice that some of the camera
images may not display in Live View. This most often occurs when you are displaying
images in 1+5 mode, or 1+7 mode because the total bit rate for all cameras is
exceeding the NVR’s capacity. The actual capacity depends on the total bit rate from all
the cameras. However, it is good practice to allow some headroom for machine
operations, such as remote streaming.
NVR model Capacity
4-channel 20 Mb
8-channel 40 Mb
16-channel 80 Mb
32-channel 160 Mb
64-channel 160 Mb
To fully understand NVR capacity, it is necessary to understand the concepts of
streaming video, resolution, quality, and bit rate. Streaming video is content sent in
compressed form over a network and processed in real time, that is, as it is received.
Streaming video types
• Main Stream: the high quality video that is being recorded and may be streamed.
• Sub Stream: never recorded; intended for streaming only. Default is
704 × 480, 584 Kbps at 8 fps.
• Can be video alone, or video and audio compressed together. Audio requires very
little bandwidth.
The combination of the main stream and sub streams make up the total bit rate of each
camera. This is expressed in Kbps (kilobits per second) or Mbps (megabits per second).
Bit rate is determined by the selected resolution (1280
× 720, 1920 × 1080,
2560 × 1920, etc.), frame rate (frames per second), and video quality (the amount of
compression being applied to each camera).
Example
32 channels of 720P cameras at 15 fps with good image quality will have
32 x (1536 + 512) = 65536 Kbps (about 66Mbps), so the 32-channel NVR can support
them.
Each channel can support a different camera, as long as they do not exceed the total bit
rate limit. It is entirely possible to mix 5 MP cameras with 4CIF IP cameras, etc.