1080p on 4K screens

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bystander36

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Apr 1, 2013
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I know TV displays are designed to try and make 1080p look better on 4K screens and people find it does look good when viewing TV continent. However, this is not done with 4:1 scaling, or it would look the same as a 1080p display.

The question is whether Nvidia and AMD have finally changed their tune an added 4:1 sacling, or has Dell added it to their monitors, or are you just finding it looks good, even if it isn't 4:1 scaling.
 

bystander36

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Apr 1, 2013
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I find that hard to believe, the fact is that 4:1 scaling is cheaper to perform than doing any kind of colour averaging and is perfectly accurate, there's literally no reason not to do it.

I find it more likely people have got shit panels and they're using on board scaler chips which are poorly designed/made and don't have things configured right.

Nvidia's control panel does not have a 4:1 option, so it seems more likely it would simply scale the same way it scales all resolutions. While it is possible to do it without giving it as an option, it is an exception that they'd have to program for.
 

PrincessFrosty

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Feb 13, 2008
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It shouldn't need a 4:1 option it should just automatically detect that the resolutions are multiples of one another and use logic to switch to a different down sampling algorithm to do 4:1, does anyone have any evidence that it's not behaving this way right now?
 

bystander36

Diamond Member
Apr 1, 2013
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It shouldn't need a 4:1 option it should just automatically detect that the resolutions are multiples of one another and use logic to switch to a different down sampling algorithm to do 4:1, does anyone have any evidence that it's not behaving this way right now?

We've had this topic before, and everyone who tried it, had poor scaling. Or at the least, it wasn't 4:1 scaling and did not look like 1080p looks on 1080p.

This is the first time anyone has come on to say they thought it looks correct, which leads me to wonder, did AMD and/or Nvidia add this type of scaling recently, does your monitor have it built in, or is it just that the scaling is done well enough, it looks good despite not being 4:1.

We can rule out part of question if you can check your CCC settings and see where the scaling is being done.
 

Ferzerp

Diamond Member
Oct 12, 1999
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I mean when I switch the display from 3840x2160 to 1920x1080 everything still looks crisp and sharp. There is none of the typical blurriness that typically comes from running an LCD and non-native resolution.

In this specific case, it was with a Dell Precision M3800.


I have the older M3800 with the 3200x1800 and it displays 1600x900 perfectly.
 

PrincessFrosty

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Feb 13, 2008
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So does anyone have a good tool or methodology for testing scaling in a precise way, some way of going full screen without any borders with exactly a 1080p and at 2160p test pattern where artefacts from scaling are clear and unambiguous.

I was thinking of making some kind of 1080p image which is a chequered grid of black and white pixels, if that scaled exactly 4:1 then it should come out perfect with clusters of 4:1 pixels, if it's scaled any other way we'd expect some kind of grey blurring?
 
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awnm

Junior Member
Aug 4, 2014
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There seem to be plenty of images out there you could use, and some 1080p YouTube test patterns, but I don't know of a specific test methodology.
 

PrincessFrosty

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Feb 13, 2008
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I quickly made these, 2 images which are chequered patters of black and white saved as pngs, one 1920x1080 and one 3840x2160. I'm not home until later to test this, but my theory is that if you can display the 1920x1080 image full screen then you should get perfect grid where the length of each grid is 2x2 pixels.

I'll try this, in several software applications and probably as my windows background as well (set to scale) and take screenshots of the desktop and publish the results.

They're here for reference - http://www.filedropper.com/tests_1

I saved them as files in a zip rather than uploading them to an image file sharing site to avoid possible lossy compressionm, it's also why I'd avoid youtube test patterns and such like, that'll be highly compressed and inaccurate to begin with.
 
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maddie

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Jul 18, 2010
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This is a topic I'm very interested in also.

If the image maps exactly to the screen whether 3840x2160 or 1920x1080, the scaling must be 4:1. How can one say it isn't scaling properly?
 

PrincessFrosty

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Feb 13, 2008
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This is a topic I'm very interested in also.

If the image maps exactly to the screen whether 3840x2160 or 1920x1080, the scaling must be 4:1. How can one say it isn't scaling properly?

Something scaled properly will be accurate with regards to the original image, something scaled badly will look different from the original image, normally differences occur when information has to be assumed/estimated/guessed.

In the case of 4k/1080p the scaling and can be done mathematically perfectly because they're divisible by each other exactly. However just because this is true doesn't mean that it will be scaled mathematically perfectly in any given implementation, it might be scaled using some function that is targeted at doing general purpose scaling for any arbitrary resolution and that could result in lossy/imperfect scaling.

A good scaler will do a check on the source and target resolution and see if it meets the criteria for perfect scaling and if it does then it will scale it perfectly (which will actually also be faster), and if the criteria for perfect scaling isn't met then it will just make a best effort scale using a general purpose scaler which will look like total trash as it's just an approximation.

A bad scaler will just ignore the possibility of perfect scaling and use a general purpose scaler which will result in a lossy scaling.
 
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maddie

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Jul 18, 2010
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Something scaled properly will be accurate with regards to the original image, something scaled badly will look different from the original image, normally differences occur when information has to be assumed/estimated/guessed.

In the case of 4k/1080p the scaling and can be done mathematically perfectly because they're divisible by each other exactly. However just because this is true doesn't mean that it will be scaled mathematically perfectly in any given implementation, it might be scaled using some function that is targeted at doing general purpose scaling for any arbitrary resolution and that could result in lossy/imperfect scaling.

A good scaler will do a check on the source and target resolution and see if it meets the criteria for perfect scaling and if it does then it will scale it perfectly (which will actually also be faster), and if the criteria for perfect scaling isn't met then it will just make a best effort scale using a general purpose scaler which will look like total trash as it's just an approximation.

A bad scaler will just ignore the possibility of perfect scaling and use a general purpose scaler which will result in a lossy scaling.

I guess one would have to know the actual mapping function used, or test the panel / Card combo.

I have a 27" Korean DVI only, no scaler panel. I can use the 4:1 function quite well. The image is softer but definitely not bad. My need is for a 4K panel for working and general use but still able to be used for gaming without breaking the bank, so to speak.
 

PrincessFrosty

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Feb 13, 2008
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I guess one would have to know the actual mapping function used, or test the panel / Card combo.

Normally scaling is only done by one thing, with the Nvidia control panel you can set specifically if the GPU will scale for you, which means the monitor receives a signal in its native res and does no scaling of its own.

OK so I've done my first test, running the test images I mentioned before by simply putting it as the desktop background has indeed revealed bad scaling, I set the native 4k wallpaper and got an obvious black/white divide in the pattern. However taking the 1080p version and setting the wallpaper to fit, windows scales it bit the whites become grey.

I took screenshots of the desktop in both cases and this is the result:

compare.png


This occurs with both Nvidia panel set to both monitor and GPU scaling and it makes no difference, so I suspect that windows scales the image internally itself, badly.

Question then becomes does windows use the same bad scaling for everything or is the desktop wallpaper one unique. I'm not sure.

I realised that VLC player allows you to display images full screen so I did the same test loading both images and again the same thing, the 2160 is noticeable white but the scale 1080p is grey both on the blacks and white. How does VLC do its scaling I wonder?

The VLC settings have the accelerated video output (overlay) setting ticked which is basically using the hardware acceleration of your video card. The Output setting for me was automatic. I've tried setting it to D3D specifically and OpenGL specifically but get the same results.

Looks like scaling by windows is pretty naff.

So I set my screen res in windows to 1920x1080 and I set my Nvidia control panel to scale by aspect ratio (so I get full screen) and tried both GPU and display scaling, both give me clear black and white using the 1080p background, so both the Nvidia drivers have no problem outputting the native res to be 1080p and scaling the output to the monitor.

perceivably when looking at the monitor either way you see grey, its just too fine of a resolution to discern the pattern, but you can see it's a much lighter grey when using the native pattern as your background rather than the scaled one so it's immediately obvious the difference.
 

awnm

Junior Member
Aug 4, 2014
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Interesting stuff. Not surprising if Windows is somehow interfering with the scaling - I wonder if W10 will fix that kind of thing, given it's mean to address the general 4K scaling issues.

If you get time, be interested to see what happens if you run up a game with the desktop set to 4K, but run the game at 1080p. Does that basically reset the monitor to 1080p and hence scaling perfectly?

Thanks for all your updates and feedback.
 

PrincessFrosty

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Feb 13, 2008
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I think if you run a game in 1080p while windows is set to 4k then it will be the Nvidia control panel that deals with scaling, so it will behave as either GPU scaling or Display scaling depending on how you have your Nvidia settings configured.

Given the perfect scaling of the drivers to upscale the desktop from 1080p to the native panel res i'd hazard a guess the output would be perfect 4:1 scaling.

However that'd be dependent on the game engine, there's nothing to stop an individual game engine dealing with scaling resolutions internally, I don't know which (if any) do this but I suspect it exists in the wild somewhere, any engines offering different rendering and display resolutions such as Arma 3 and Battlefield I'd suspect are likely of doing this, how well they do it is up to them.

1080p scaled 4:1 at 32" actually doesn't look as terrible as I thought it would, that's going to be very usable on the 27" models which a lot of people have for 1080p anyway.
 

bystander36

Diamond Member
Apr 1, 2013
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I think if you run a game in 1080p while windows is set to 4k then it will be the Nvidia control panel that deals with scaling, so it will behave as either GPU scaling or Display scaling depending on how you have your Nvidia settings configured.

Given the perfect scaling of the drivers to upscale the desktop from 1080p to the native panel res i'd hazard a guess the output would be perfect 4:1 scaling.

However that'd be dependent on the game engine, there's nothing to stop an individual game engine dealing with scaling resolutions internally, I don't know which (if any) do this but I suspect it exists in the wild somewhere, any engines offering different rendering and display resolutions such as Arma 3 and Battlefield I'd suspect are likely of doing this, how well they do it is up to them.

1080p scaled 4:1 at 32" actually doesn't look as terrible as I thought it would, that's going to be very usable on the 27" models which a lot of people have for 1080p anyway.

The game would not handle scaling, as it has no idea that you are using a lower resolution. It just renders to what ever resolution you set it to. After that, it is up the GPU or display to scale it. Games would have to give an option to scale it, which I guess some have done that in the past, but in the opposite direction. Like BF4 having a 200% resolution scale, which becomes more like down sampling.
 

Jumpem

Lifer
Sep 21, 2000
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Following this. I have wondered if demanding games could be run at 1920x1080 on 4k monitors.
 

PrincessFrosty

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The game would not handle scaling, as it has no idea that you are using a lower resolution. It just renders to what ever resolution you set it to. After that, it is up the GPU or display to scale it. Games would have to give an option to scale it, which I guess some have done that in the past, but in the opposite direction. Like BF4 having a 200% resolution scale, which becomes more like down sampling.

Most games behave like this but some don't, engines like the Arma series allow you to set a rendering resolution and a display resolution which scales the resolutions to match. I was playing Ark today and that has a similar scale factor option.
 

bystander36

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Apr 1, 2013
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Most games behave like this but some don't, engines like the Arma series allow you to set a rendering resolution and a display resolution which scales the resolutions to match. I was playing Ark today and that has a similar scale factor option.

That's my point. There are very few like it (I don't own any of them), so for the most part, games don't know the resolution of your monitor, on the resolution you tell it to render at.

And yeah, there are rare exceptions.
 

Man I Suck

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Apr 21, 2015
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1080P doesn't look great on any display > 24'' anyway...

For example, a 27'' 1080P display only has about 60% of the pixel density of a 27'' 1440P equivalent. I can't imagine 1080P on any desktop displays over 30''...

Oh, I dunno.

I'm using 1080p on a 40" HDTV that's about 8 feet from my face. It looks pretty good to me. :)
 

jtw473

Junior Member
Jun 13, 2011
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My Panasonic l65wt600 I got in 2013 has built in 4x1 pixel scaling, it will even scale 1440p to 4k. I have no idea why Nvidia or AMD does not support it through drivers.

dsc00881j0s4m.jpg
 

shady28

Platinum Member
Apr 11, 2004
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Debating a 1440p vs 4K screen.

If I’m happy with 1080p for the time being, are there arguments against running 1080p on a 4k screen until video cards that can drive 4K become affordable?

The scaling shouldn't be an issue, and you get the advantage of 4K for non gaming uses. Plus for non demanding games 4K should be usable even now.

Given monitors are upgraded far less often than cards, seems like buying something like the well reviewed 4K BenQ 3201 now and playing your games at 1080p for a while is more future proof than buying a 1440p screen only to replace it in a year or two.


I looked at some 4K desktop screens and quickly came to the conclusion that the desktop is not yet optimized for it. Even if you get default font / icon sizes right, too many applications will wind up with tiny unreadable text on sub 32" monitors and you'll constantly need to zoom in.

Or, you'll run your monitor in a scaling mode at 1080p, which means you don't really get to take advantage of the extra screen real estate.

If you spend 90%+ of your time on the PC in a game, maybe 4K is ok if you have the hardware to run it decently.

And the market is not adopting 4k quickly at all. 768p and 1080p are still the fastest growing screen resolutions on desktop according to Steam. So at 1440p, I don't think you'll need to replace the monitor in 2 years. More like 4 or 5. Honestly I think 1440p is the ideal resolution for both a gamer and someone looking for more productive screen real estate on their PC.
 

SERPENTINE

Member
Jun 21, 2015
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You should just stick with 1920x1080 if you're looking to game.
A lot of games in 4K don't run well especially with multiple monitors.
 

Jumpem

Lifer
Sep 21, 2000
10,757
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My Panasonic l65wt600 I got in 2013 has built in 4x1 pixel scaling, it will even scale 1440p to 4k. I have no idea why Nvidia or AMD does not support it through drivers.

dsc00881j0s4m.jpg

This is exactly what I want a monitor or Nvidia drivers to do.