Impossible to stream from QuickTime to TV with AirPlay

Hello,

I've searched all over the internet and haven't been able to find a solution for this, so now I'm gonna have a go at it myself:

AirPlay-streaming to my smart TV (Sony Bravia X85K) works just fine in most cases. I can mirror my Mac-screen, I can stream from my iPhone and I can use AirPlay with a number of streaming services. But AirPlay-streaming videofiles directly from QuickTime simply does not work. When I select my TV as output-source, the TV gives me the message "Connected to Mac," but the video file doesn't play.

Several users on other fora have stated that the issue persists with other brands of TVs as well, and many conclude that the problem is a QuickTime-problem, since they are all able to use AirPlay with their TVs for other things, like screen-mirroring, or using their phone. Noone I'm aware of have been able to find a solution to the problem.

I've tried all the basic usual steps. Restarting computer, resetting the TV, etc. and I'm positive this is not due to some mundane oversight on my part. It seems to be a bug in how QuickTime "communicates" with Smart TVs.

Did anyone find a solution?