How to preserve portrait mode of iPhone recording in iMovie and Final Cut Pro?
I had this problem just last night, editing portrait iPhone X video in iMovie. Here’s how I got around it:


In iMovie, when I added my video clips and titles and such to the timeline, I used the ‘Cropping’ edit panel to rotate them all 90° anti-clockwise. It’s weird editing video that’s lying on its side, but I got used to it.


After exporting from iMovie to a .mov file, I used Handbrake to transcode it to a smaller .mp4 file (which I usually do anyway). In Handbrake’s ‘Picture’ tab there’s a ‘Rotate’ filter; I used that to rotate it back 90° clockwise.



I’m sure you could do something similar on the command line with FFMPEG too.