Recording video on mac without mirror inversion
Shift+Command+H will flip a video horizontally in QuickTime after you stop recording.

In summary:


Record a video in QuickTime as usual (it will still show as inverted during this time)
Stop recording
Shift+Command+H to flip it horizontally
Quit the app - it will prompt you to save the file, which will save it in the desired inversion. Alternatively you can File > Export to a variety of formats.


I tested this on macOS Catalina using QuickTime 10.5.