Thanks for the links,
I tried to add an exception for vimeo, but it doesn't seem to have any effect. Also tried adding exceptions for video MIME types, still no luck.
I guess I have to disable "Real Site" completely to be able to watch vimeo normally.
To be honest I've had so much bad experience with Avast blocking things and not being able to add any rules or exceptions, that I'll switch to another software as soon as my license ends.
I've started another thread, looking for help with avast firewall blocking my printing, remote desktop and DLNA. Tried everything to add exceptions there too, with no luck. This is just rubbish.