[TimoJ]

Also noticed that anytime I seek forwards/backwards during playback, the screen will go black for a split-second, I think to display the buffering overlay. This is a little jarring, especially when it happens on locally stored files, maybe it should only appear after some small delay?

I also have this same problem when I skip or switch to play from FF. Black flash after each skip. Not sure when it started, I was using #0504 before and it didn't have this problem.   

For nvidia this is known. VDPAU is on its way into the grave. Currently no developer owns nvidia GPU anymore and therefore no on is working on it. Hopefully it's reproducable with AMD + VDPAU - else it looks bad.  

Yes, Nvidia had very long black pauses. But I'm now using Intel Haswell and it has these short black flashes.