Hi, Tstack,
You are not overlooking any setting. At the moment, iMovie has a 16:9 horizontal aspect ratio that cannot be changed. Vertical 9:16 clips will be displayed and exported with black bars on each side to make it fit iMovie's 16:9 screen dimensions.
However, there are three ways to export a 9:16 vertical clip without black bars.
- You can rotate the 9:16 clip sideways with the rotation controls in the Crop feature. Export it sideways to your desktop. Open it in QuickTimePlayer. Rotate it right side up (Edit/Rotate). There will be no black bars.
2.You can go to the projects browser screen (where your projects are displayed as icons) and do a File/New App Preview. That will open a screen that looks like the normal project screen, except that it will have fewer features. Import a vertical 9:16 clip into the timeline. When you export the New App Preview (a designated option in the file export box) the vertical clip will export without the black bars.
3.Another way is to export a normal project with a vertical clip that has the black bars on each size Then play the video on the desktop. Use the Command-Shift-5 feature to drag select around the video to create a screen recording that eliminates the black bars.
-- Rich