Overscan correction for 720p playback on 1080p screens

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Overscan correction for 720p playback on 1080p screens

I have both the original and the new Apple TV. With the original model, you could set Apple TV to output in 1080p, set your TV to display in "Full Pixel" mode, and never have to deal with overscan.

The new model only outputs in 720p mode and appears to have a fair bit of overscanning. This is tolerable in movies and movie trailers but very annoying when watching screencasts in YouTube (e.g., game replays on the hdstarcraft channel) because all the screen edges are cropped.

Any suggestions?

The TV (a Sony Bravia W 4100 series) offers Full Pixel mode for all HDMI inputs but this setting is missing in action for the same input when the signal is 720p (and yes, I tried setting it to Full Pixel by first connecting the old Apple TV and then plugging the new one in). The only options available for the 720p signal from the new box are: Wide Zoom, Full, H Stretch, and Zoom.

I tried toggling the Service Menu on my TV to change the overscan compensation but no luck there either... this model doesn't seem to have such an option. Now what? Boxee has a nice way of compensating for overscan.... I don't see anything like this for the Apple TV. Did I miss it? Not that I'm surprised... they like to keep things simple.

Wouldn't the simplest, cleverest, most obvious answer be to enable 1080p output from the Apple TV 2 just like the original model? It can still process 720p content like it has always done (the merits of that are a separate discussion!) but this would allow modern HDTV's to do 1:1 pixel mapping without getting into overscan compensation issues.

So... is there any way to enable the 1080p output setting that we enjoyed with the original models?

iMac 24" 2.8 Ghz, Mac OS X (10.6.5)

Posted on Jan 1, 2011 3:17 PM

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Answer 1

Alley_Cat

Level 7

20,548 points

Jan 2, 2011 9:41 AM in response to jetlagged

Short answer, no.

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Answer 2

Chenks

Level 5

7,435 points

Jan 2, 2011 9:43 AM in response to jetlagged

it's not the appletv that is overscanning, it's the TV.
my TV is configured correctly (ie with no overscan), and the appletv displays everything on screen.

the problem you have is with your TV, not the appletv.

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Answer 3

jetlagged Author

Level 1

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Jan 3, 2011 2:10 AM in response to Chenks

Yes, I realize that. But a quick glance at several threads on avsforums.com suggests that a large number of HDTV's have this problem. Think about it -- 1080p sets can only do "full pixel" mapping for 1080p sources. All other resolutions need to be mapped and scaled to the native resolution and this inevitably introduces overscan.

For that matter... how can you be sure that your TV's is configured correctly? Have you tested it with any calibration signals? Try displaying an image that is sized 1280x720 with a 1 pixel border... if your set displays the border correctly on all sides then congratulations... you have a very rare set!

The first generation Apple TV didn't have this issue because it could output in 1080p, even though the content itself was 720p. And while some HDTV's allow overscan compensation to be adjusted through the service menu, that isn't something most people will be comfortable with.

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Answer 4

Chenks

Level 5

7,435 points

Jan 3, 2011 2:57 AM in response to jetlagged

jetlagged wrote:
For that matter... how can you be sure that your TV's is configured correctly? Have you tested it with any calibration signals? Try displaying an image that is sized 1280x720 with a 1 pixel border... if your set displays the border correctly on all sides then congratulations... you have a very rare set!

yes i have tested it with the appropriate test patterns.
no i don't have a rare set, i just have a good one that does what it is supposed to do.

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Answer 5

Alley_Cat

Level 7

20,548 points

Jan 3, 2011 3:22 AM in response to jetlagged

jetlagged wrote:
Yes, I realize that. But a quick glance at several threads on avsforums.com suggests that a large number of HDTV's have this problem. Think about it -- 1080p sets can only do "full pixel" mapping for 1080p sources. All other resolutions need to be mapped and scaled to the native resolution and this inevitably introduces overscan.

It's the TV's job to scale non-native resolution material to display at native resolution.

Your TV is undoubtedly upscaling the 720p signal and overscanning it effectively upscaling beyond 1080p - this is not Apple TV's fault.

There is no reason the TV hardware should not be able to upscale to exactly 1080p and do 1:1 pixel mapping if it has this option - if the manufacturer hasn't implemented this sort of feature th eproblem is with the TV.

I have one plasma that overscales, another that maps 1:1. It's the individual sets not AppleTV.

That said, I would not object to an overscan adjustment in AppleTV's menus but I doubt average users would want to fiddle with that if they didn't want to fiddle with their own TV settings.

Having an adjustment in AppleTV assumes the hardware is capable of doing so (as with a TV), it may not be. You don't generally see overscan adjustments say on a PS3, DVD player etc...

The new Mac Mini with HDMI has very effective fine granularity overscan adjustment - much better than my old mini I used to connect via DVI.

Why not request an adjustemnt using:

http://www.apple.com/feedback/appletv.html

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