*Sub-Thread* Dithering in GTA4

Discussion in 'Console Technology' started by Laa-Yosh, Apr 28, 2008.

  1. Laa-Yosh

    Laa-Yosh I can has custom title?
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    Just for a little fun, I've done the following to an x360 screenshot in Photoshop:
    1. crop to 1120x630
    2. apply gaussian blur, 0.5 pixels
    3. resize to 1280x720

    And voila, almost all the dithering is gone.
    Now I'm not sure how big the Quincunx filter is supposed to be, and even though I guess 0.5 should be pretty close, anyone more privy should feel free to correct me on this one.

    [​IMG]

    Edit: this also means that if your TV isn't 1280x720 native, then its scaler will probably remove a lot of the 'dithering' from the x360 version, but not as much as PS3's additional blur with the Quincunx AA. I wonder if new HDTVs only have sharpen filters or they can do blurs as well...?
     
  2. Mintmaster

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    The fence is just the same problems we've always had with alpha-tested textures, and it's not the same problem as in the screenshots.

    Alpha blending is a pretty good solution, but it doesn't look as good when you're close up.
     
  3. Mintmaster

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    Regarding the dithering, it looks like it's from the shadow mapping. Looks like they're doing 4 jittered point samples. This screenshot is pretty much a worst case, but I suspect that it would look better in motion.

    Kind of a weird choice, though, and doesn't look well done in still images. Needs more depth bias and the sampling radius is too big.
     
  4. Thowllly

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    The 360 version look sharper. But for some reason the BurgerShot sign hanging from the roof looks pixelated/aliased/dithered and hard to read in the 360 shot, but nice and clear in the ps3 shot. Whats up with that?



    Sorry if this has already been discussed/explained, haven't been following the thread....
     
  5. Hazuki Ryu

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    Probably a matter of contrast/color settings
     
  6. Jesus2006

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    No, it's the "dithering" effect again:

    360:
    [​IMG]

    PS3:
    [​IMG]

    Also:

    360:

    [​IMG]

    PS3:
    [​IMG]
     
  7. -tkf-

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    In regards to videos, this wont show up unless you make uncompressed video captures. That dithering will be smoothed out.
     
  8. deepbrown

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    Sorry to ask if this has been answred already - what causes this dithering, and why does one console have it and the other not?
     
  9. TrungGap

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    If you notice it's only on the lettering but not so much on the arrow or anything else...I would guess artistic license/style.
     
  10. deepbrown

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    Well...if it's artistic style, why doesnt the ps3 version have it? Once again sorry if this has been looked at in the detail....this thread got kind of messy.
     
  11. Dopefish

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    I don't know if the PS3 dithers or not. It might dither... but because of the upscaling (and added blur), the dithering effect might be diminished. This is just my speculation, though.
     
  12. -tkf-

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    It seems to be connected to depth of field/lod. Apparently it doesn´t need to show up in motion, as mentioned by Laa-Yosh (video captures are void on this since as i mentioned it would be blurred/smoothed out). This is one of those things that might end up looking completly different depending on what TV you use.

    Quaz took a shot at an explanation, but i am not sure he still has the same opinion.
     
  13. szymku

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    In my opinion, strange dithering in xo version comes from higher compression of textures...
    It looks like some kind of compression artifacts
     
  14. xatnys

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    This has somehow made its way to Kotaku; I would be on the lookout for potential newcomers.

    I do agree that it's interesting that resolution isn't necessarily the dominant factor in visuals for GTA4.
     
  15. TrungGap

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    It can't be compression, because the lines of the lettering are well defined with no artifacts on the outside. It's only on the inside. Look at the blue circle around the burger, on the 360 is look clean whereas the PS3 looks a little muddy. This is probably because of the lower resolution.
     
  16. aaronspink

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    Laa-Yosh already did a test where he applied a blur filter and partial upscalling to a cropped 360 image and it comes out looking pretty much the same as the PS3 image. The conclusion is that the upscaling on the PS3 image is actually removing the dithering.

    Aaron Spink
    speaking for myself inc.
     
  17. Laa-Yosh

    Laa-Yosh I can has custom title?
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    The dithering itself is probably a result of a post processing filter effect that runs on decreased precision, or generates this result intentionally.

    But it is hardly visible on any TV, especially compared to your average LCD computer monitor. Developers nowadays test games on a variety of displays and it's safe to assume that Rockstar checked GTA4 on both 768p and 1080p LCD and plasma TVs so they knew what they were doing.
     
  18. MazingerDUDE

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    I doubt that this is the case. I got the PS3 version, and the shadows dither like hell. If the upscaling is able to remove the dithering, it should do the same on the shadows.
     
  19. Rockster

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    Dithering: To me it seems like the 360 version doesn't use alpha blending for the DOF effect and the PS3 version does. Maybe a result of the limited number of alpha bits when using fp10?
     
  20. LightHeaven

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    When i played the game on 360 i got the impression that there was some kind of filter to make distant objetcs look like oil painted...

    It looks really weird, and i'm not really sure if thats how its supposed to look, but since it really look like that in a lot of cases the impression i have is that this is what they tried to achieve.

    That filter not only looks strange, but also detract a lot from the IQ, because its really flickering...

    I had to to sit farther from the screen because all the flickering happening in the background (and that hasn't happened in any game that i have played on 360 ant has DoF applied to them) really bothered me...

    Seeing these pictures posted here, it looks to me that the dithering is just the "filter" acting... And i think it looks even worse in motion...

    But i haven't got the game yet, probaly will in a week or so, i just played in my friend's house for a few hours...
     

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