Crushed blacks when downsampling in exclusive fullscreen

Discussion in 'Videocards - NVIDIA GeForce Drivers Section' started by MaLDo, Oct 10, 2017.

  1. MaLDo

    MaLDo Master Guru

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    Hi, I'm suffering a problem for a few months. I can't remember the exact date it started but is really annoying.

    I usually use custom resolutions for gaming. And I usually prefer exclusive fullscreen mode because a lot of games have better framepacing in this mode.

    The problem is that downsampled resolutions show crushed blacks when used in games in exclusive fullscreen mode. This problem doesn't happen in desktop if I use a higher custom resolution, and doesn't happen if I play the game in borderless mode after increasing the desktop resolution. For example, in my 1080p TV, using 4K downsampled in desktop, colors and contrast is perfect. But if I start a game at 4K in exclusive mode, I lost a lot of shadow detail. It's like contrast values are wrong.


    Ideas?

    Thank you!
     
    Last edited: Oct 10, 2017
  2. MaLDo

    MaLDo Master Guru

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    If I knew it I would have written it in the forum way before. Right after posting the message I went to the Chagne resolutions tab in nvidia control panel and changed point 3 to "Nvidia color configuration", 12bpc and YCbCr444 format and that fixed the problem. Before I was only messing with scaling options and Desktop Color configuration tab in nvidia control panel. Facepalm.
     
  3. dr_rus

    dr_rus Ancient Guru

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    Windows is really weird at how it sets the video out by itself. It's like MS just use a randomizer.
     
  4. Mda400

    Mda400 Master Guru

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    If you are getting black crush, Your HDTV is set to expect limited range signals such as YCbCr instead of RGB.

    YCbCr is only used for compressed material such as DVD/Bluray. You want to try and get it working with RGB first as that is the colorspace all computer-generated content is produced in.

    If its a premium brand, it will have this feature most likely named black level/HDMI video mode in its advanced settings (some, like Sony for instance, use a picture mode such as "graphics" to switch this).

    When using exclusive fullscreen mode, the application has control of what the display properties are set to, not the desktop/nvidia control panel. The resolution or refresh rate can dictate which colorspace an application tells the graphics card to send to the display (i.e 1024x768@60hz vesa/PC vs 1280x720@59.94hz CEA/video/broadcast).
     
    Last edited: Oct 11, 2017
    Redemption80 likes this.

  5. Sajittarius

    Sajittarius Master Guru

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    You shouldn't be able to set both 12bpc and ycbcr444 for 4k, current HDMI doesn't have the bandwidth. Whenever i try to do that on my computer, it will force it to 8bit. Ycbcr422 12bit works, it forces the tv into HDR mode. This is all in 4k though.

    It might work in 1080p for the desktop, and then its just switching to 8bit ycbcr444 for the exclusive 4k fullscreen (if its ycbcr for desktop and fullscreen that would explain why the blacks aren't being crushed anymore).

    A lot of people recommend RGB for everything. I used to follow this but now i have an HDR TV and the only way to make sure things don't get weird when switching to HDR content is to just keep everything ycbcr. Yes all games are created on PC's but a lot of them are tuned to look good on consoles, so they generally look great in ycbcr, plus movies are tuned for it.
     
  6. Apparatus

    Apparatus Master Guru

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    The whole thing between ycbcr444 vs rgb full is very confusing.
    I used rgb full as long as I remember my self.
    Now with a new Samsung 4k tv I thought to make a little research, but the topic turned out to be huge.
    Most people propose ycbcr444 when using a TV, and full rgb when using a pc monitor.
    As we proceed with the years though, I found out that the most recent suggestions(2016, 2017) are for the rgb full option even for tvs.
    And the latest trend is something like : if your tv supports full rgb, then choose full rgb on your vgas control panel.
    I am in the middle of a long screenshots comparisons project, and my first impressions are that the best option is :
    nvcpl : full rgb
    samsung : pc mode+uhd hdmi color : on+hdmi black level : auto(greyed out)
     
  7. dr_rus

    dr_rus Ancient Guru

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    ycbcr444 is always limited, RGB gives both options. If your TV support full dynamic range, use RGB+Full, if not - it doesn't matter, RGB Limited=ycbcr444.
     
  8. Sajittarius

    Sajittarius Master Guru

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    Yea i always used full RGB on the last TV i had, but since this one does HDR (and current HDR is always ycbcr420 or ycbcr422), I stuck with limited.

    If you don't have a specific reason to use ycbcr, then Full Range RGB is usually better.

    Incidentally, if you change the Digital Vibrance setting in the nvidia control panel "Adjust Desktop Color Settings", it forces Full Range, even if you are set to Limited in the Resolution section. This will cause black crush; and if you are using ycbcr, the TV usually wont even let you select Full range since ycbcr shouldnt even be sent in that format. The only way to fix it is to keep digital vibrance at 50 and force change from full rgb and back to limited in the nvidia settings.

    So yea, if you like the digital vibrance nvcp feature, that is one more reason to always use Full Range RGB.
     
  9. MrBonk

    MrBonk Ancient Guru

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    The TV usually has option for the HDMI range.

    Another thing might be if for some reason it is using a 16-bit color resolution , which crushes the gamma with DSR
     
  10. Mda400

    Mda400 Master Guru

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    Only because as you stated, you are bandwidth limited. Otherwise RGB is superior to YCbCr as it is uncompressed/unaltered color and the display draws the image in RGB (its subpixel colors) so even if you send the display a YCbCr signal, the display will have to convert it to RGB internally anyways.

    Whatever creates the least amount of color conversion steps will produce the best quality with the least delay. Using RGB, you are setup to not need any conversion steps. Console games are still 'tuned' to RGB, they are computers after all.

    Live footage needs to be compressed as its not as easily controlled motion or color-wise as computer-generated content and produces more data needed to be stored, so we use YCbCr , xvYCC, etc. to be able to transfer that unproportional data.
     
    Last edited: Oct 20, 2017

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