Hi when I take video with my Phantom3 it is very jerky and stop starts any idea what Im doing wrong/ Thanks in advance for the help

Once again, better to post this on the Phantom 3 forum. However, there are a number of issues that can cause your problem. It may simply be that you are not panning smoothly enough. You may need to look at adjusting the yaw expo and smoothing out the gimbal settings. You will probably need to post a short video so people can see what the issue may be.
I have a Mavic Pro and P4Pro so other Phantom 3 users may offer better assistance.