# Forcing Motion Detection to a Specific Stream

Navigation: Working with Nx Witness > Device Management (Cameras, Encoders and I/O Modules) > Setting Up Cameras and Devices > Working With Expert Device Settings > # Forcing Motion Detection to a Specific Stream |

Nx Witness performs motion detection on the server side by analyzing and decoding the secondary stream from a camera, which is usually a low resolution stream while the primary stream is high-resolution.

Occasionally, a camera will report its configuration incorrectly and swap the primary and secondary streams. If this occurs and the secondary stream is high-resolution, motion detection processing will create a very high CPU load.

To correct this, it is possible to force motion detection on to a specific stream.

1.Open the Camera Settings -> Expert tab.

2.Check Force motion detection for stream and select Primary or Secondary.

3.Click Apply, OK or Cancel.

IMPORTANT: Adjusting these settings may seriously affect server performance!