How to record in 16:9?

Hi there guys. After watching some Let's Plays, I really wanted to do one for PoP, but for youtube to record high def, I need a 16:9 resolution. Now my game only allows 1680x1050. Does anyone have a fix / solution on how I can play at 1920:1080?

Maybe check this
http://www.geforce.com/whats-new/articles/dynamic-super-resolution-instantly-improves-your-games-with-4k-quality-graphics

AMD should have something similar for Radeon carts.

Or play in window mode.

Check this thread as well
https://obsproject.com/forum/threads/has-anyone-with-a-1050p-monitor-tried-upscaling-via-adjusting-the-custom-base-resolution-to-1080p.19285/