I've finally found a solution!!
Option + Click 'Editor' in the Menu bar's Preferences.
Select (Quicktime) (if not displayed, you may have to restart QC).
Change the Default width and height to your preferred resolution.
I've finally found a solution!!
Option + Click 'Editor' in the Menu bar's Preferences.
Select (Quicktime) (if not displayed, you may have to restart QC).
Change the Default width and height to your preferred resolution.