The variable bit rate mode means the bandwidth used by the camera will vary according to what the camera is seeing and the video profile settings. The video profile settings for the variable bit rate mode are resolution, frame rate and image quality. High resolution creates more data than medium or low resolution (see following sections for more detail). The degree of motion present in a video stream also affects the amount of data created.

The constant bit rate mode means the bandwidth used by the camera will stay relatively constant regardless of what the camera is seeing. The constant bit rate mode is therefore more predictable in deployments where bandwidth and/or storage capacities are important considerations. The video profile settings for the constant bit rate mode are resolution, frame rate and bit rate. The bandwidth used by the stream is dictated by the bit rate setting.

In general, using the variable bit rate mode results in relatively consistent video quality but fluctuating bandwidth and using the constant bit rate mode results in varying video quality but predictable bandwidth. Choosing a high bandwidth constant bit rate mode avoids the video quality drop e.g. during high motion, but may use some unnecessary bandwidth during times of no activity.

However, in most cases the difference in video quality between the variable and constant bit modes is negligible (assuming the same resolution and frame rates) and the constant bit rate mode produces more reliable output from the cameras.