Tips for Brightness Fluctuations on HDTVs (reply to Mac Mini/Samsung HDTV user)
Got an email from a mac Mini/Samsung HDTV user about annoying brightness changes during (iTunes) movie playback. I first asked he ensure the Mac didn't have any odd display/contrast settings in "Universal Access" but not sure my mails are getting through. What I'm suggesting here are general TV settings tips to try, including some Samsung specific. These may not solve everyone's problems, but here's a few notes and tips:
Check the TV's settings for automatic backlight adjustment and energy savings. (Samsung calls it "ECO" mode in the "System" menu which also has an Energy Saving sub-menu.) Try disabling any auto/ECO/Energy saving mode or feature.
Check for any 'Dynamic Contrast' (or similar name/function) in the TV's settings. Even if you prefer it enabled (at some level), disable it as a test of its effect on any brightness changes you're seeing. (You may find you're able to leave it at 'low' without any negative effects, but when troubleshooting (or calibrating) turn it off.)
Again as a test, Check any "Auto Motion" settings (dejudder, frame interpolation, smoothing, etc) and turn it off.' (Some Samsung owners prefer it set to "Clear" or a Custom" (0 Dejudder) setting.) Dejudder/interpolation often adds a "Soap Opera" effect and can also cause artifacts/distortion on some scenes. (For a distortion test, try a scene with a person moving/running that also has a grid pattern or wire fence in the background.)
For some Samsung models, selecting "Movie" mode disables an auto dimming feature. The backlight may still turn off completely during a full black screen. (For TVs that do that, some of the worst examples are during a movie's end credits that cycle between an all black screen to the text credits on an otherwise black screen. For example The Dark Knight Rises end credits.)
Another common tip for some Samsung HDTVs is setting brightness (which is really black level) above 45, but this may not disable all the auto dimming. There's also a "Motion Lighting" and "LED Motion Plus" setting (BFI?) in some models that in my experience darkens the screen (sometimes not immediately).
Some TVs have a PC or Game mode to try but that may also disable other picture adjustment features. (It may also cause the mac to use RGB vs. YCbCr (TV) mode which solved some mac/TV/monitor issues in the past without using other tricks.)
Most LCD owners already know this, but disabling dimming features (and brighter screens) make any 'flashlighting' and clouding more visible however, especially if edge-lit. (Some later/higher end LCD Samsung models have a "Cinema Black" feature that turns off LEDs in the black bars area of widescreen movies that helps mask issues like this, which unfortunately are fairly common with many edge-lit displays.)
For the record I've used a late 2012 Mac Mini with a 2012 Samsung ES series HDTV via HDMI through an AVR (setup noted here) without any problems with movies/videos (DVDs and OTA TV HD recordings from EyeTV). I don't use iTunes for movies however, just the OS X DVD Player and Quicktime player. I have seen/dealt with the Samsung's auto-dimming however as well as workarounds for other things (like infamous "V" cloud from the LCD timing board heat). Overall I'm happy with its performance and PQ in general but it has its share of edge-lit/ultra thin design faults. (The ES is a long-term loaner from a friend that I'm thankful to have after my CCFL LCD failed.)
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