Sometimes using the crop filter does not work right, your video ended up grainy and fuzzy. And there is no more crop in rendering stage like older versions. Here're two alternatives.
1. create new project
2. do a custom setup, set your custom frame size for your final target, and pick your codec.
Sometimes the ok button will malfunction, you won't response and you can't create a new project, you have to start over in that case..
(in method two, set frame size to your initial frame size, you will crop in AME later)
4. import you asset
.5. drag video to timeline, drag around the preview in program window until you get your ROI.
6. export with AME
7. Set the final video to the same as your project. (change fit to 100% if it is smaller than preview window)
(in method two, you use the crop feature [circled green in illustration] to change the desired final size instead. You can drag around the preview for ROI placement. Make sure final frame size is same as crop.)