I used to be able to edit my Virb videos in full without any jerkiness etc in v.5.2.1, however since that version I have to use Fast (720) in order for it not to be jerky. Problems, is trying to work out what's a good image or not. Why has this changed? Has anyone else had these issues? If I was still using 10.13 I'd simply revert to 5.2.1.. But I'm not. (Or not yet..)
I believe that the fast vs. full only applied to editing, and when you export, it will use the settings in the export screen. That means you should be able to use fast, and still export in full resolution.