OPTIONS_MAXFPS

This field has certain limitations when used for non-local devices.
Failure to adhere to these limitations will cause a delay in live video, irregular frame skipping, and missed events
For streaming IP cameras, do not use this field to reduce the frame rate. Set the frame rate in the camera, instead. You can, however, use a value that is slightly higher than the frame rate in the camera. In this case, this helps keep the cpu from being overtaxed in the event of a network problem.
Some, mostly older, IP cameras support snapshot mode. In this case ZoneMinder is actively polling the camera for new images. In this case, it is safe to use the field.