Resurrecting this old thread since this issue came up again today...a relative was using my phone and recorded a video in portrait mode. She wanted to edit it later using iMovie, but we found that the crop made it unusable, because the action was taking place outside of where iMovie forced us to crop the image.
Is there still no way to adjust the crop within the app (or to not use a crop at all)? Although the crop isn't the real issue--it's that iMovie doesn't seem to give any options about where that crop falls.
And if iMovie can't do it, can anyone suggest a good video editing app that can? Something that allows you to take a portrait-oriented video and decide for yourself which part to keep, or that at least gives you an onscreen viewfinder while shooting so you can see what part will be saved?