I have a 2011 27" iMac that currently has Mountain Lion installed on it, and I am trying to get the AirPlay mirroring to take up my entire 1080p widescreen TV. How do I get that to happen?

2 Answers 2


Try setting the Match Desktop Size To setting in the AirPlay menubar item to Apple TV

Airplay menu

If that doesn't work, it may be that AirPlay is outputting at 720p and your TV isn't scaling - perhaps try a stretch or scale mode on your TV.

  • I already did that. I was trying to play a DVD from "DVD Player", and when I set the desktop size to AppleTV it only takes up about 1/3 of the screen starting in the upper left corner. And when I set the desktop size to the AppleTV when my iMac is not running the DVD Player, it will take up 2/3 of the screen starting at the top and centered.
    – tarheel
    Commented Aug 5, 2012 at 13:36

Click "Open Display Preferences" in the AirPlay menu (as shown above). Set the resolution on your TV to 1080p. The key, at least in my case, and I suspect in yours, is to click "overscan correction", which will get that last 1~5% black border to go away.

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