Cropping sources
Sometimes you only want to record a portion of your screen.
For example: You don't want the dock and menu bar of your Mac to be recorded.
The best way to achieve this is to create a virtual camera using OBS.
1  Download 
OBS from their website
 and install it.
2  Open OBS and click on Settings -> Video.
Set as both the "Base Resolution" and Canvas Resolution the resolution of your
desired output. We recommend 1920x1080. Click on OK.
3  Under Sources, add your display.
4  Crop the video by dragging on the corners of the video.
5  Click on Start Virtual Camera.
6  In the Remotion 
Recording interface
, you can now select "OBS Virtual Camera" as the source.