DVI-HDMI Mirror Display Quality Issues

Discussion in 'Mac Basics and Help' started by Si737, May 9, 2009.

  1. Si737 macrumors newbie

    May 9, 2009
    I recently bought a dvi-hdmi adapter, hdmi cable, and jack-split phono cables so i could watch films on tv from my macbook

    But when i connect them and change the aspect ratios and colours etc, the quality is just not what i expected..
    The top, left, right, and bottom of the picture is cut out, and the whole thing is patchy and pixilated.

    Is it not supposed to be great quality?
    Or would it be the cables i bought? the settings?

    Any idea?

    Help would be amazing, thanks,
    Simon =]
  2. dolphin842 macrumors 65816

    Jul 14, 2004
    The success of hooking up Macs to TVs is largely dependent on the specific TV... some do perfectly fine with the connection while others mess it up.

    Two quick points to consider:

    1) Is Overscan turned on? You should see an option in the Display preference pane for the TV. If you uncheck it, you may get rid of the cutoff.

    2) If you are in mirror mode, is the resolution set to the TV's resolution? Mirror mode will default to lowest common resolution between the two displays. Try turning off the mirroring and see if that helps.
  3. WhoPhD macrumors member

    Feb 4, 2004
    You might also find a huge difference when enabling or disabling interlacing. Having said that, it's a little bit scary to do this yourself the first time, because you need to get familiar with DisplayConfigX (a must-have utility for the HTPC Mac).

    You'll probably find that the HDMI port is enforcing a suggestion from the TV that the computer please provide some native 1080i pictures, for instance. But for most new TVs, 1080p is no big deal.

    Anyway, before I forced it from 1080i to 1080p, the "cleartype" sub-pixel font smoothing was completely screwed up, and I couldn't even work out exactly why. It's as if the TV just had a very subtle failure to line up the sub-pixels. This was even after I lined up the picture and chopped off the black areas and un-chopped the cropped areas.

    So good luck ... make sure you have a spare LCD lying around to plug in, in case your Mac decides it wants to give your TV an invalid resolution, and you need to reset the settings. It happens.

  4. WhoPhD macrumors member

    Feb 4, 2004
    Oh, I just noticed you're using a Macbook, unlike my "headless" Mac Mini, so that'll serve as your backup display.

    Also, I found (to my complete surprise!) that the DVI port supplies the HDMI cable with audio. I had get my Geek Licence suspended after that shock.

  5. dolphin842 macrumors 65816

    Jul 14, 2004
    The DVI connection on a macbook passes audio? Do you have a link to corroborate this? I thought DVI by itself is incapable of passing audio.
  6. n-abounds macrumors 6502a


    Mar 6, 2006
    I had this problem on the new 22" Samsung monitor i bought. When I plug in my macbook, I get some horrible/fuzzy resolution (aka the Macbook's usual resolution but on a bigger screen). But when I run it in clamshell mode (lid closed, plugged-in, asleep, woken with mouse), the resolution is much better (1680x1050). So maybe try running it in clamshell mode?

    It's also strange cause this doesn't happen at all when I hook it up to the 50" tv- is automatically displays better whether or not it's in clamshell mode.

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