Is there a way to play in one resolution and stream in another?

[Zatios]

I have a big monitor (odyssey G9) and I stream at 1080 but I want to play games on full screen and stream aswell to a resolution that most people can enjoy full screen as well. Is there a way for me to pay in one resolution but stream in another?

just in case it matters:

I have a 2nd pc to stream from and a capture card there.

 

[PaiSand]

Yes.
I recommend you to start here: https://obsproject.com/wiki/OBS-Studio-Quickstart

 

[koala]

The Odyssey G9 is a ultra widescreen monitor with aspect ratio 32:9. This is like 2 ordinary 16:9 monitors next to each other. If you want to stream your gameplay, you need to either use only half of that monitor for your game, or you crop half of your game screen and show only half (for example the center), or you add black bars to the top and to the bottom.

There is no magic in the world that allows you to play fullscreen and at the same time show your viewers (who usually have 16:9 monitors) the same fullscreen without black bars or without half of the video being cut.