The angle of the curve at the ViewerFrame dictates the velocity. A flat curve (horizontal handle) means the object is stopping. A steep curve (vertical handle) means the object is exploding with speed.
In the context of these camera web interfaces, the mode parameter in the URL determines how the video stream is delivered to the browser: viewerframe mode motion work
To make the most of your motion work within a viewerframe, consider these technical tweaks: The angle of the curve at the ViewerFrame