What does "Ignore Film Grain"/Grain Rejection do exactly for Nvidia's new Sharpen Feature?

Discussion in 'Videocards - NVIDIA GeForce Drivers Section' started by BlindBison, Nov 3, 2019.

  1. BlindBison

    BlindBison Master Guru

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    Hi there guys,

    I've recently been experimenting with Nvidia's new Sharpen feature and noticed this value defaulted to 17% (or 1/6) when enabled from the control panel.

    My question is, does this do more than just "Ignore Film Grain"? If not, then this setting shouldn't do anything at all in games with Film Grain disabled, but so far it appears to have an effect in each game I've tested where games look more "grainy" or "sandy" with this setting lower it seems (though perhaps this simply means in the games I've tested thus far, they force some form of film grain in their post pipeline).

    I would expect that one would want to exclude Film Grain from being sharpened by the filter (a value of 100% I would think for Ignore Film Grain provided I'm understanding all this correctly -- I may not be), but if this is so, then why would Nvidia Default it to a value of 15%?

    I noticed in techspot's article here: https://www.techspot.com/review/1903-dlss-vs-freestyle-vs-ris/ that they refer to this setting as "Grain Rejection". Does this imply the setting is more complex than simply bypassing sharpening the film grain?

    I really don't understand why one would want to sharpen the film grain effect so I expect I am seriously missing something in all this.

    Anyway, I haven't been able to find more information regarding this setting so does anyone know exactly what it does? Thank you for your time, I appreciate it.
     
    Last edited: Dec 2, 2019
  2. RealNC

    RealNC Ancient Guru

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    If the game has film grain, then without this, the grain is going to also be sharpened. If you don't like that, then use that option. "Ignore" and "reject" mean the same thing here.

    That's about it, really.
     
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  3. BlindBison

    BlindBison Master Guru

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    Alright, great -- thanks mate.
     
  4. BlindBison

    BlindBison Master Guru

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    Posting an update on this thread since I've done some more testing in other games with this setting:

    I could be missing something of course, but this setting does appear to do more than simply ignore any post process film grain a game may have as I've tested it in games that you can turn the film grain OFF in where this slider still seems to effect the image quality in a discernible way.

    For example, even with Film Grain unchecked in the graphics settings, this setting still appears to affect the amount of inner detail that gets sharpened in each game I've tested so far. After messing around with this slider a good bit, I think the default Nvidia's gone with (1/6 or 17% in the control panel) seems like a pretty decent value overall so I'll just leave it at the default setting.

    Usually I find 50% sharpening to be a bit too much -- Crysis 3 for example is already doing 25% sharpening and in my experience a mild amount of sharpening paired with TAA or any post AA that blurs the image seems to do a nice job of recovering some sharpness without the noticeable artifacts that can come along with oversharpening an image (but it is pretty subjective of course which looks preferable).
     

  5. RealNC

    RealNC Ancient Guru

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    Of course. The algorithm can't actually know with absolute certainty what is film grain and what is not. Other stuff is going to be affected as well.

    Also, if you lie and enable "ignore grain" but then disable film grain in the game, the algorithm still thinks there is film grain because you told it so. So, uh, don't do that? :p
     
  6. Cyberdyne

    Cyberdyne Ancient Guru

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    It just ignores noisy detail in general. A more accurate name would have been "Ignore High Frequency Detail". But i guess film grain is more commonly understood.
     
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  7. BlindBison

    BlindBison Master Guru

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  8. AQUILES

    AQUILES Master Guru

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    "ignore film grain" is a filter focused mainly to counteract the excess grain generated in films and videos when there is too much sharpness.
     
  9. PQED

    PQED Active Member

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    I know I'm (very) late to the party, but i don't think this is its' purpose at all.

    Instead, it removes noise on textures created by the sharpening filter, which will of course increase with higher settings.
    I verified this on the character select screen of Star Trek Online where it was very obvious when noise due to increased sharpening occured.

    I'm also posting this only because it's currently the top result if you google "nvidia Ignore film grain" (or at least it is for me).
     
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  10. HeavyHemi

    HeavyHemi Ancient Guru

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    As someone posted right above you, a better term would have been "Ignore High Frequency Detail" versus Ignore film grain.
     

  11. PQED

    PQED Active Member

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    I saw that, but it probably isn't going to be obvious to everyone reading this thread what that means, which is why I decided to clarify.

    Edit: In hindsight I should probably have quoted that post instead to make it clearer.
     
    Last edited: Dec 2, 2019
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  12. BlindBison

    BlindBison Master Guru

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    @PQED I appreciate your comment, I think it was helpful for clarifying personally.
     
  13. -Tj-

    -Tj- Ancient Guru

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    I tested it a lot in Destiny2 and came to conclusion it sucks xD. Ignore film grain made it look bad no matter what. I'm not using it for gpu scalling, just downsampling @ ingame supersampling 135%.



    Also tried normal sharpen slider and even 0.10 was almost too much, I used ignore up to 0.60.. Negative driver LOD made it look sharper without those artifacts, although it made tiny bit shimmer in the distance, seen mostly on fence metal type of floors. Same as by DOOM3 for example - only on fence metal surfaces.
     
    Last edited: Dec 3, 2019
  14. nanogenesis

    nanogenesis Maha Guru

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    Now thats a term I haven't heard in quite a while. How does one go around setting it? Last I tried it didn't seem to work.
     
  15. -Tj-

    -Tj- Ancient Guru

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    Yeah, but it worked.. tested in
    Destiny
    GTA5
    RIFT
    Huntshowdown

    there is a option in nvinspctor driver controlled lod, you can turn that off too if it doesn't work.
     

  16. 0458315753

    0458315753 Active Member

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    Can someone clarify when the "ignore film grain" option is disabled? As the OP said, it (still) currently defaults to 0.17 (ranges between 0 and 1).

    I wonder if some static noise can be introduced in games which have no film grain or any similar effects.
     
  17. Lurk

    Lurk Member Guru

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    this is the way I take it:

    - slider set all the way to the right (value=1) ---> no sharpening applied to whatever noise the algorithm interprets as film grain

    - slider all the way to the left (value=0) --> sharpening applied at its fullest, including on the aforementioned noise.

    I'd like some clarification on this myself.
    the way the feature is presented can indeed create confusion.
    It would have probably been much more idiot-proof (myself included) if they provided an 'enable film grain sharpening' checkbox, and then a slider for the percentage of sharpening to be applied. duh.
     
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  18. Cyberdyne

    Cyberdyne Ancient Guru

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    Your best bet, unfortunately, is to try it out using FreeStyle. It's the same filter, and you can see the changes in action.
    Visually, having ignore grain too high makes the output look kinda like an oil painting. It tends to only sharpen edges, looks blotchy.

    Probably based on the contrast of the scene.
    High contrast parts (sudden charges in color/brightness, aka "edges") remain sharpened with high "ignore grain".
    This is not something you want. You're ignoring too much detail, details that you typically want a sharpen filter to sharpen.

    Low contrast parts of the scene contain those details you want sharpened, but unfortunately film grain by it's very nature is also high detail (noise) low contrast (color/brightness change is based on what's under it, in other words film grain on a green object the pixels will still be green). Unless it's an obnoxiously aggressive film grain, then there can be a lot of random brightness change, but I guess that's why you've got that slider.
     
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  19. Lurk

    Lurk Member Guru

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    well, sounds more complex than I thought.
    the problem with Freestyle is that most of the latest games I've played do not support it :(
     
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  20. aufkrawall2

    aufkrawall2 Master Guru

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    Well, just start a game and try to tell if it looks pleasing.
    I personally prefer a "ignore grain" value of 0.25, though I only use sharpen strength from 0.05 to 0.15 to counter blurry AA.
     

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