Can iTunes be made to play Apple ProRes files? My videos encoded as Apple ProRes are playable in Quicktime but not in iTunes.  Is there anything I can do to make iTunes play them?

Apple's support page suggests to me that iTunes can play any .MOV file:


  QuickTime and MPEG-4 movie files that end in ".mov", ".m4v", or ".mp4"
  and are playable in QuickTime Player.


but this does not seem to be the case in my testing, instead I find that I am unable to add the files to the iTunes library. There is no error dialog.
On 24 of July I tried for some hours to get iTunes 12.x (actual version at this time) to play other 3rd Party Codecs. In short: I was not successful. iTunes has changed a lot, so none of the older hacks work anymore.

I'm very interested in a solution for this problem, because I have a lot of FLAC-Files I would love to manage in iTunes. If I find a solution I will update this answer and provide a "Tutorial".