I have a set of Super 8 movies, digitized to Full HD MP4. This results in black bars left and right. I've imported the movies into Final Cut Pro x 10.4, with those bars. After doing some editing, I prefer to export them without the bars to a 1440x1080 resolution. I can create a project with that resolution. I can crop the clips to that resolution, but if I export it, I get 1920x1080. I don't know what I doing wrong.
Handbrake removes these bars automatically, but exports to 30fps while the movies are 24fps. And I prefer to export directly from FCP.
How can I export movies without the black bars?