I just started using FCP and still haven't got the hang of it, I'm having problems where my video is letter boxing and when Export it gets squished. Also when I export in 4:3, Pinkbike seems not to recognize the format. There may already be threads out there on this but I just need some opinions and examples of what to do.
FCP operates on sequence settings and export settings. If you have the new FCP it will auto recognize your footage settings if you drag it into a fresh sequence, so that should be a give in. If not you can right click your media and figure out the settings its at.
As per exporting if you go file > export > quicktime mov is that the correct aspect and so forth?