I've sifted through a lot of "black screen" threads and ruled that my problem is not like those. See the picture below. My video (right) is playing. OBS is capturing the audio, but the visual remains black. I thought perhaps it was the video source, but after trying multiple videos, I found they all had this problem. I also tried running this on 4 different computers which means I think there is something wrong with my settings, but I've tried altering the settings and they either make the problem worse (whole screen goes black) or do nothing at all.