Question / Help capture in 4k portrait mode

[peterbrinson]

I'd like to capture my 4K game, but at 2160 x 3840, like you see below, as I set my Windows Display settings to 'portrait'.
(I'm making a trailer for a phone game and I want good resolution in order to zoom in).

I tinkered with OBS this afternoon and I couldn't get it to work. All the captured videos are wider than tall, and therefore cut off the top and bottom. Thanks for your help.

 

[R1CH]

Just type in the resolution you want in the video settings.

 

[peterbrinson]

Ah, you can type directly into the dropdown interface. Thank you.
You can see here that I'm very close. Why do I have these black borders? It doesn't look this way when I'm capturing.