I think I found out myself after a few hours of testing around. The option to reduce black bars was set to off, I set it to 20% and nothing changed, than back to off and everything works again. Seems somehow the system had 20% as default but didn't show it somehow.
Oh, and happy new year everyone. 
Hello,
after the update, every movie and TV show just shows without the black borders. I use the "normal" image setting like always, but everywhere the black bars are gone and I have to manually set the pixel ratio to 1.16 or similar so the picture is okay again (Long faces are a really ugly thing when you watch classics like Blade Runner.)
Any ideas what happened? This just happened after the update to 10.0.1, with 10.0.0 everything was fine.
