120fps is usually used for slow motion. My normal use setting is 1080p/60fps/medium/spot meter on. Do not turn on "Auto Low Light" even though it helps you see in the dark spot. All GoPros in general have a huge weakness which is darkness. In fact, every camera's weakness is darkness because it requires low ISO (longer exposure time) to capture a better quality image but at a slow snap which can create blur. When you enable Auto Low Light, it will constantly adjust FPS to accommodate your dark and bright spots. Because it's adjusting between like 24fps to 60 fps (if you set the fps to 60, 60 is the highest it will go), this will produce a jumpy footage like you mentioned or a laggy or skippy motion. I think this is quite the dumbest option I have ever seen but it's understandable why they made it because some people want to improve the dark footages. You are sacrificing video smooth play for a more clear (less grainy, video noise) footage. Lower FPS, better quality in dark. Higher FPS, worse quality in dark because exposure time is too fast on high FPS. You don't have to turn Spot Meter on but I do sometimes to keep the object I'm filming in the middle have a good lighting initially.Did you adjust many settings for video? My clips seem jumpy and grainy. Mine is set to 720p at 120fps.