Ticking the “camera in motion” box keeps the image straight and aligned with the horizon whatever the position of the camera.
The stabilization process can also be used to avoid crooked horizon if the camera is shaking (during a movement).
You can also feel the need of putting the camera in place upside-down. In this case, once the installation is done, you can tick the “camera in motion” to level the image of the camera.
You can also rotate the view of the camera manually using the Yaw, Pitch and Roll value. Add a value between -359 to 359 and click on the “rotate” button to apply it.
It is possible to reset the value pressing the reset button.