MBP > Airplay > Apple TV mirror image not filling television screen

[jmc1978]

Mid 2012 13" MBP Mountain Lion / Apple TV (3rd gen) / Vizio 37" 1080p Television

When I use Airplay to mirror to Apple TV the image I get on the television shrinks. The image never fills the television screen. I measured and I only get a 35" image on the 37" screen. Everything down to the text shrinks. The image sits inside black on all four sides. I've tried every scenario I can think of with settings. Nothing is working. I found a few threads on the web and tried what they suggested and nothing has changed. Eveything from image auto setting on Apple TV to overscan on MBP.

When I Airplay with my iPhone 4 everything is fine. Video fills the television.

I can play a video with my MBP via Home Share through iTunes and it fits the television perfectly fine. Now when I watch the same video through just Quicktime and Airplay the video will not fill the television. I get the shrunk 35" image. On a side note I also get extreme lag and stutter playing a video via Airplay alone. However, the same video will play flawlessly via Home Share iTunes.

Another example would be HBO GO via iPhone Airplay fits the television perfectly fine. When I stream HBO GO from MBP Airplay I get the shrunk 35" image.

Any help at getting a true MBP screen mirrored to my televison via Apple TV? Am I doing something wrong? Did the sales person at Apple lie to me when I asked if I could mirror full res from my MBP? I'm not just concerned about video playback. I was hoping to use it for applications like FCP. Thanks!!!

 

[waw74]

once you've started airplay, hit the airplay menu again, and select "match desktop size to... appleTV"
you will then have black bars on your mac's screen.

the screens aren't the same aspect ratio that's why you have the black bars.
in order to keep the image correct (a circle stays a circle, and doesn't turn into an oval) you have to have the bars on one screen or the other.
your mac is 16:10 your TV is 16:9. This means if your mac and TV screens were the same width, the mac would be a bit taller.

when you play the file via home sharing, the aTV plays the file directly. (this is also what happens from your other iOS devices, unless you are using mirroring there)
the video is pre-encoded, so all of the heavy processing is already done to it.

when you play the file on the mac or iOS, and use airplay mirroring, the mac plays the file, it then captures the video output of your screen, and re-encodes it to the airplay format, and sends it over the network. this is why it doesn't look as good, and tends to stutter. in much the same way that a photocopy of a photograph isn't as sharp.

*one small difference to this, is mirroring on iOS, if you are mirroring, and you watch a video (and the app supports direct airplay) it will switch over to regular airplay, you iOS screen will show the airplay icon, and controls for playback, and the video will be sent directly to the aTV for playback.
--although you say you have a 4, so no mirroring for you, everything you do is direct airplay.