Im new to FCPX in the last 5 months. I have been uploading to youtube with not problems. The last few videos I have uploaded have been a different aspect ratio then my others. This video here is a square box, not the 16:9. Im not sure what I have done to make it that way, but Id like it to be full screen. I use a GoPro hero 4 an a magic pro drone. I Usually shoot in 4k. any help would be great.