Screen dims in itunes based on video content

Question

When watching a video in iTunes my screen dims based on the content of the video to such a level that it's very hard to see anything. This only happens when the content of the video is actually dark at the moment (eg shadows, at night). When the content of the video switches back to something brighter (eg daylight) the brightness is going up again and everything is fine.
When the screen goes dark and I move the mouse (to bring up the player controls), the screen switches back to bright right away. Until the controls go away, then the screen goes back to dark. I've also tried to play the video in other player and the same problem doesn't appear. Interesting to note is also that this only happens when playing videos in itunes in full screen, when the player isn't in full screen the screen doesn't dim.
I've checked the energy saver and accessibility settings and nothing is set to dim the display. I've also turned off any energy saving settings on my tv. However, as this only happens in itunes and not with VLC I don't think this would be causing the problem anyway.
I'm using OS X Mavericks on a Mac Mini connected to a Samsung tv via HDMI.
Any help would be very much appreciated.

Answer 1

I just upgraded my tv from 55" led samsung tv 1080p 120hz, to a newer model samsung with the same specs but with smart capabilities. I've noticed that since the swapping of TVs, the dimming isn't nearly as prominent. While the dimming still happens, tweaking the settings of the tv may help out a bit. I know that on some of the movies/tv shows I've watched with the old settings, in especially dark scenes (horror and thrillers mostly) much of the experience was lost due to the inability to make out images on the screen because of the darkness. I'm still searching for solutions, and trying different things. It may help if we all post a list of what we are using, and any other info that might prove useful. Maybe we all having a setting turned in that is causing this.
TV= 55" Samsung 1080p 120Hz
Connection to TV = Rocketfish brand HDMI to Mini
- iTunes library is stored on a 4Tb hard drive to play content through computer. I pull content from the hard drive, I don't stream wirelessly.
- in iTunes I have the playback video set to always be on top of other windows, as well as in a separate window unless the window is full screened.
- my computer sleeps after 15 minutes. I can't remember if I have tried turning off the sleep function; however, I don't think this is what is effecting the playback because the dimming takes place in just a few seconds, rather than several minutes.
I have worked with Apple Support and tried several solutions suggested. I attempted to create a second user to confirm that it wasn't a setting I had changed for my personal login that was causing the dimming. I have re-installed iTunes and restored to default settings. I was told that maybe apps I had running in the background such as WJoY or Caffeine could possibly be causing interference, turning these background apps off didn't change anything.
Like I said, changing some of the settings on my TV helped. The only other work around that I might suggest until we find a solution, is moving the playback bar with the volume and ff/rw and play buttons to the corners utensil you can only see a small sliver, then leaving the cursor on top of the playback bar. This causes the bar to stay visible and not hide, whilst keeping mostly everything out of site. You'll still have the close screen (X) in the top left of the screen, and also be able to see the playback bar just a little bit, but it is better than nothing.