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1080p DVI/HDMI Nvidia overscan compensation and 1:1 pixel mapping.

2880 Views 14 Replies 5 Participants Last post by StratMangler, Oct 6, 2006

lstepnio

Discussion Starter · Sep 29, 2006

Is it possible to achieve 1:1 pixel mapping on a 1080p Samsung (HLS6088W) while outputing in the native 1080p resolution of 1920Ã—[email protected] and using the overscan compensation adjustments in the Nvidia drivers?

The question really being is if the overscan compensation adjusts the physically outputed resolution to the display device? Does the overscan compensation maintain native output at 1920x1080p and to compensate for the overscan with a virtual resolution maintaining the 1:1 pixel mapping at the physical [email protected] resolution?

Does anyone have have 1:1 pixel mapping with overscan compensation working on 1080p display with a DVI->HDMI Nvidia 7xxxGS/GT video card?

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1 - 15 of 15 Posts

Killefitt

· #2 · Sep 29, 2006

I have a 6600GT on a SXRD A2000 and it works great on the latest (as of about a month ago) driver. I dont know which driver release off hand. It recognizes the display as a SonyTV and I choose to output 720P (or 1080P) then go to advanced settings and choose 4 or 5% overscan compensation, which still outputs 1920x1080 to the TV but it shrinks your desktop into a 1866x988 (or whatever) area to fit on your screen. the result is sharp text for a desktop and internet etc.

I did read a recent post about a Mitsu TV not having the overscan adjust option with Nvidia driver though so not sure what the deal was there but it works on mine.

Rod

lstepnio

Discussion Starter · #3 · Sep 30, 2006

Quote:

Originally Posted by Killefitt
I have a 6600GT on a SXRD A2000 and it works great on the latest (as of about a month ago) driver. I dont know which driver release off hand. It recognizes the display as a SonyTV and I choose to output 720P (or 1080P) then go to advanced settings and choose 4 or 5% overscan compensation, which still outputs 1920x1080 to the TV but it shrinks your desktop into a 1866x988 (or whatever) area to fit on your screen. the result is sharp text for a desktop and internet etc.

I did read a recent post about a Mitsu TV not having the overscan adjust option with Nvidia driver though so not sure what the deal was there but it works on mine.

Rod

When playing full screen video does the overscan compensation still kick in? It would be ideal if it didn't so you didn't end up with a screwy resolution when playing video.

StratMangler

· #4 · Sep 30, 2006

This may sound like a dumb question, but honestly... if your bringing down your resolution something like 1866x988 (as was mentioned earlier), doesn't that *NOT* become 1080P? 1080P is 1900x1080 and only that. No?

Otherwise, aren't you entirely destroying the concept of 1:1 pixel mapping to begin with?

moto316

· #5 · Oct 2, 2006

i would also like to know how to properly output 1080p to my HL-S5687 from my 7800gtx and get it pixel mapped 1:1 perfectly without screwing around with custom resolutions

lstepnio

Discussion Starter · #6 · Oct 2, 2006

Yes, 1866x988 does not become 1080p as far as available pixels being output from the windows OS goes. Using a virtual resolution which is set to 1966x988 with a physcial output of 1900x1080 you will still get 1:1 pixel mapping. The display will still get 1900x1080 so no display scaling will occur.

This virtual resolution is ideal for the windows desktop output without overscan but you wouldn't want use a virtual resolution when outputing video fullscreen where a little overscan isn't an issue.

moto316, the odds are that you can't.

JKohn

· #7 · Oct 2, 2006

Quote:

Originally Posted by moto316
i would also like to know how to properly output 1080p to my HL-S5687 from my 7800gtx and get it pixel mapped 1:1 perfectly without screwing around with custom resolutions

Well for starters, with that particular set I believe you have to go into the service menu and disable electronic overscan, and due to a firmware bug you'd have to do this every time you turn on the set. (This was my reason for choosing to go with the new MIts DLP).

Even then, it's not possible to get a 1920x1080p desktop with both 1:1 mapping and zero overscan from a rear-projection set. Overscan is just a fact of life with these sets.

StratMangler

· #8 · Oct 2, 2006

Quote:

Originally Posted by lstepnio
Yes, 1866x988 does not become 1080p as far as available pixels being output from the windows OS goes. Using a virtual resolution which is set to 1966x988 with a physcial output of 1900x1080 you will still get 1:1 pixel mapping. The display will still get 1900x1080 so no display scaling will occur.

Huh???

How does that make sense? I can understand if you purposefully overshoot the 1900 with 1966 and the little bit of overscan that occurs offsets the extra pixels to 1900 perfectly (depending on the set), but how can 988 pixels give you 1080 pixels with 1:1 mapping? That just doesn't make sense at all. Unless I'm missing something, here? Color me confused.

lstepnio

Discussion Starter · #9 · Oct 2, 2006

Quote:

Originally Posted by JKohn
Well for starters, with that particular set I believe you have to go into the service menu and disable electronic overscan, and due to a firmware bug you'd have to do this every time you turn on the set. (This was my reason for choosing to go with the new MIts DLP).

Even then, it's not possible to get a 1920x1080p desktop with both 1:1 mapping and zero overscan from a rear-projection set. Overscan is just a fact of life with these sets.

That bug you're referring to is only with the HLSxx87W models and not the HLSxx88W model that I have. I already have software overscan disabled and it has no problem sticking.

I don't care about about having the virtual desktop at exactly 1920x1080p as long as it's 1:1 with no overscan which I think totally possible. The only time I will care about having 1020x1080p with 1:1 (with some overscan) is when ZoomPlayer goes fullscreen.

There is a feature in ZoomPlayer to switch resolution when switching to fullscreen and I'm pretty sure will will allow me to switch between the desktop no-overscan odd-ball "virtual" resolution I create to the native 1920x1080p resolution when I go fullscreen.

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JKohn

· #10 · Oct 2, 2006

Quote:

Originally Posted by lstepnio
That bug you're referring to is only with the HLSxx87W models and not the HLSxx88W model that I have. I already have software overscan disabled and it has no problem sticking.

True, but the post I replied to mentioned the 87, and the 87 is also the model most people are going to see because it's the one carried by the "big box" stores. I couldn't justify the price difference between the 87 and 88 just to get a firmware bugfix, so when the Mits 2007 models came out it was an easy choice.

lstepnio

Discussion Starter · #11 · Oct 2, 2006

Quote:

Originally Posted by StratMangler
Huh???

How does that make sense? I can understand if you purposefully overshoot the 1900 with 1966 and the little bit of overscan that occurs offsets the extra pixels to 1900 perfectly (depending on the set), but how can 988 pixels give you 1080 pixels with 1:1 mapping? That just doesn't make sense at all. Unless I'm missing something, here? Color me confused.

I think you're missing that we're talking about a virtual resolution and not the resolution that the video card is sending to the display. This mean that only the windows desktop is aware of 1966x988 (for example). The video driver is drawing black space in the overscan space between 1966x988 and 1920x1080. You're still getting 1:1 pixel mapping. You still get 1:1 inside windows regardless of the resolution. The whole issue with 1:1 is with display scaling the pixels.

StratMangler

· #12 · Oct 4, 2006

So essentially, you're fooling your display into showing the whole image *with* 1:1 pixel mapping by over-extending the resolution?

lstepnio

Discussion Starter · #13 · Oct 4, 2006

Here is the FAQ post for Power Strip describing exactly what I'm referring to:

http://www.entechtaiwan.net/forums/viewtopic.php?t=27

Quote:

"resolution-in-a-resolution":

1. PowerStrip menu > Display profiles > Configure

2. Switch to the overscanned/underscanned but otherwise satisfactory resolution (ie: 1:1 pixel mapping) if you're not there already

3. Click Advanced timing options > Custom resolutions

4. Check "Lock total geometry"

5. Reduce/increase the number of "Active pixels" by the estimated amount of overscan/underscan, e.g., if you are at 1920x540 and there is ~ 5% overscan, change the number of active pixels to 1824x514

6. Click "Add resolution" and follow the instructions on screen

This second method, of course, only works if your display driver supports user-defined resolutions.

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Killefitt

· #14 · Oct 5, 2006

Yes for the windows desktop it outputs 1080p at 1:1 to the TV. graphically, if you could see it, the outer border of your desktop is black bars. the more overscan compensation you choose in the Nvidia driver, the bigger it makes these black bars, to "shrink" your usable desktop to fit on your visible tv screen. great for internet, e-mail and anything else you do in windows.

when you watch full screen video it will still have the overscan, which is the way it is supposed to be. if you have "windowed mode" maximized video then the video itself is no longer 1:1, it gets shrunk to the visible desktop, but my eyes on my 1080p TV can't tell the difference on 1080p movie clips, still looks amazing.

For games on the otherhand, you have to play them at 1:1 with overscan (some bottom buttons might be off your screen) or some newer games (I play world of warcraft) have your virtual resolution of 1966x988 available to choose from, which will fit the game on your screen but any text or sharp details in the game gets a little fuzzy as its no longer 1:1

a simple idea but hard to explain!

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StratMangler

· #15 · Oct 6, 2006

Thanks for taking the time to explain it to me.

1 - 15 of 15 Posts

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