OBS Studio 3440x1440p letterboxing

[Puns1234]

So just started streaming and noticed in twitch the game is very squished. Due to me having a 3440x1440p monitor.



How do I make it so it just letterboxes instead of being squished? In OBS Studio that is.

 

[FerretBomb]

You'll need to set your Base Canvas to a 16:9 aspect ratio resolution, in Settings->Video. You can just type it in, don't have to select from the dropdown.
As far as I was aware, Twitch automatically letterboxes any incoming video stream to 16:9, it shouldn't squish the aspect ratio.