Mirillis forum

Is there a way I can record my webcam into a separate track? Sometimes when I record webcam, it blocks parts of the game. I use Sony Vegas Pro to edit my videos (QuackQualityHD), and I want to be able to transition my webcam fading away when ever it blocks parts of my game, and restore it. DanTDM can and Jacksepticeye can, I just wonder how they do that?
"quak" -QuackQualityHD