# fixing overscan

## mrpringle

Hi,

is there any way to fix or compensate for overscan issues when driving a HD LCD TV (1920x1080)

The edges seem to get cropped by about 10%.

I've got a nvidia 8800GT and I'm using the 169.12 drivers. I'm going to build a custom PC and run mythtv on it so I may end up with a different video card later on. Are there any cards which can compensate for this issue better than others?

Cheers

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## bunder

strange... i have a 6600gt in my myth box, and i get a fairly decent picture...  in fact my recordings ignore overscan, so i get a bigger image than what i would see if i was watching it on normal tv...

now if only i could tell my framebuffer and/or xorg to draw the screen 5 pixels to the left, and 5 pixels up...   :Laughing: 

sorry, i know that doesn't help much, but this might... tried different resolutions?  i don't own a widescreen tv, but you might want to try 1024x768.

cheers

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## mrpringle

i can run at lower resolutions without any overscanning, but obviously i would prefer to be able to run at the native res.

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## bunder

how high can you go before it starts drawing off-screen?  does your tv have resize controls like computer monitors do?

cheers

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## mrpringle

Everything under and including 720i/p seems fine.

I still do not completely understand the overscanning problem. The TV can display 1920x1080 pixels, so if my video card is set to 1920x1080, how come pixels are being chopped of the edges of the display? Is my video card not outputting the correct resolution?

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## bunder

how are you configuring xorg... modelines or just specifying the resolution?  maybe the video card can't read the tv properly at 1920x1280.

does 1920x1200 work at all?  not sure if that's the correct aspect ratio though.   :Confused: 

cheers

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## Akkara

TVs have historically needed wider (longer in time) hsync and vsync intervals compared to computer monitors and especially compared to LCDs. Perhaps HDTVs carry on this legacy even though their LCDs wouldn't be constrained like that.

If that's the issue, lengthening your hsync and vsync may fix it.

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## mrpringle

For the moment I'm going to get a VGA cable and see if that helps at all.

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