I am curious. I see that most of the other messages about this conversation were from August 2016. I'm wondering if you have solved the problem of your gimbal or not. I watched the video and I've not seen anything like that before. It's almost as if you were flying a fixed wing model, not a
hex a-copter or quad-copter.
If you still have the problem, have you found the 'hidden' calibration test page in your ST16? Or have you checked the "Hardware Monitor" screen to see if all switches & levers are centered? Particularly, the K1 knob & K2 lever.
If not, let me know and I'll try to help guide you to the 'Hidden Calibration' page so you can do a complete calibration and hopefully make the camera & gimbal work properly again.