In basketball this is called the “Hail Mary shot” 
I don’t know anything about this, but I quickly found this one on the forum:
If you want to give it a try…
Edit: Disregard, of course, I misread the post and thought OBS worked badly, not that it didn’t.
Regarding v4l2sink, I see in the pinned comments on the AUR that it is not required anymore, for v4l2loopback-dkms I guess you already tried both the arch and AUR git versions…
No idea, sorry…