*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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    I think it'd be more interesting to talk about the technical background of this issue, as - honestly - it doesn't really matter to me while playing the game.

    It's been hinted that it should be possible to solve the problem relatively simply, but why wouldn't Rockstar fix it then? Considering how many complex technological issues they've adressed properly, and how incredibly polished the game in general is, I find it hard to believe that what we see is not intentional...
     
  2. speedsix

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    I'm finding the 360 palette very much on the warm side (I would say my screen is calibrated correctly and not overly cool like alot of sets, upscaled 1080p via vga) I've not seen the PS3 version in motion but I can't imagine any more warmth would be preferable.

    Has anyone done a comparison between versions on the same screen calibrated properly for each machine?
     
  3. B1663r

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    speedsix,

    I don't think it is possible to calibrate color "correctly" in terms of "best". I know in the color printing business you calibrate to standards, so that when the service bureau takes a project, the customer gets the colors that they expected.

    I know in the audiophilia and videophilia markets, there are people who will "calibrate" the color/audio of your home theater. IMO, on consumer gear these guys are snake oil salesmen. On a given piece of consumer equiptment you are gonna get what the particular device gives you. On the sales floor at circuit city and best buy, the customers equate brigter hotter colors with quality and the loudness of a stereo with quality... But neither of these represent "accurate" reproduction.

    There are also physiological limits like it or not. Audio quality surpassed (conclusively) human hear ability many years ago. The CD released like 25 years ago now brought that perfect reproduction to the masses.

    In video, it is a harder nut to crack. No video format I know of comes even remotely close to human limits of perception. Even the most naive of viewers can tell the difference between any picture of an Apple, presented in any format, and a real apple, sitting there in front of them. So knowing that every visual presentation is going to be an artistic rendering there is no "better" there is only "accurately reproduces the source material"

    In this case, the PS3 has its own source material, and the xbox has its own source material.

    If people find the PS3 version better, it is because it lacks the artifacts like the shimmer and moire patters that I find really disorienting in the xbox version. I think this thread has more or less concluded (well I have anyhow) that is a function of the PS3 downscaling the image.

    I think a patch to GTA IV that at least gave xbox users the option to run this game at 640p, like the PS3 version, would be a simple fix (but what do I know?) and effectively make both versions identical.
     
  4. B1663r

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    Also... Gametrailers.com has a video up that is the first example I have found that captures the xbox shimmer and moire in action. Although, on a computer screen it does not accuratly represent the effect it has sitting 4-5 feet away from a 42inch TV.
     
  5. Mintmaster

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    I think that theory got tossed out the window. It now seems like every texture that isn't magnified is affected. The decal textures just have more identifiable features.

    (By the way, decals are small textures that you superimpose on a larger object without having to do an additional texture access everywhere, or make new texture coordinates on the whole model. Usually you make additional geometry to achieve this, but there are several methods around. Texture re-use can be done without resorting to decals.)
     
    #105 Mintmaster, May 2, 2008
    Last edited by a moderator: May 2, 2008
  6. Mintmaster

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    No other multiplatform game has shown any difference in tone like this, and techincally speaking there really shouldn't be one.

    Part of the issue with tone comparisons is that the time of day is always changing. However, there are some PS3 screenshots where the light is more yellowish than any 360 shot, and you even see a shift this way indoors. My guess is that it was an artistic tweak implemented by the guys that coded the PS3 renderer.
     
  7. chachi

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    I don't think that's what people have concluded at all. Mintmaster has suggested that the clearer decals in the 480p version are a result of downscaling but I'm not sure that's the full story either.

    To me the dithering looks like some kind of effect to give detail to low-res art assets and it is being misapplied and/or has issues on certain types of assets, like the sign decal. Maybe in 480p and the known downsampling blurriness R* doesn't apply as much of the low-res art hiding shader? There may also be more than one factor at work (the suggested misalignment error) but it's hard to say unless you're R*.

    That wouldn't solve anything, it'd just make the current situation blurrier. A patch to disable the shader that does the obfuscation would make more sense, but then people would complain about the low-res art assets. :)
     
  8. Mintmaster

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    That was just to clear up the "mystery" of why the dither problems went away with 480p output.

    I don't think that's a good explanation because the dither shows up when the sign is farther away, i.e. when the texture has plenty of information for the number of pixels, but goes away when the sign is close and you can see the low res texture (like here).

    As for the 480p captures, again, there is no difference as it's still renders to a 720p framebuffer. I hope this quells any doubts about it:
     

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  9. btdvox

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    Its interesting to see that some people state the PS3 640 p to be superior to the 360 version, To me the PS3 has always rendered things warmer toned than the 360 which is fine, it give sit a nice look in alot of games like resistance, heavenly sword etc. But to me using my 1080p tv the 360 version is quite a bit sharper and cleaner than the ps3, though i do see dithering in the 360 it is also there on the ps3 version, I still have both versions at my house and am still trying to nit pick at certain things.Thing is taking photos from my TV dosent do any justice and im not a decent photographer in any sense anyways.

    To speculate though - I dont htink the two versions have any difference in AA- i beleive its just the way its being rendered and how the filters on each system apply which has been stated many times b4.

    People stating the PS3 having 2XAAQ vs 2XAA or supersampling for alpha textures on a certain system have no source and are just pulling things out there butt. I do notice a tad bit more AA on the 360 and thats simply because its a sharper picture overall anyways.
     
  10. Mintmaster

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    The resolution differences are confirmed and there's no doubt. PS3 has no AA and 360 has 2xAA.

    Any dithering that the PS3 has come from issues that plague all games, like shadowing, alpha testing, edge aliasing, etc. However, the 360 has an additional source of dithering in a bunch of textures - maybe every texture - and that's what we're trying to figure out. (The shadowing too, but that's understood.)

    So someone with the 360 version: Does that "BurgerShot" sign get messed up gradually and uniformly when you slowly move away from it, or do pixels suddenly change one at a time? How about the "Memory Lanes" sign or the ads on the wall?
     
  11. Philip42

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    http://static.videogamer.com/videogamer/images/pub/misc/vsapril29large4.jpg

    Look at this screenshot, and you'll notice(don't ask me why) the intersection on the PS3 version is less pixelated and better filtered?(whatever the right word is here), the thrashcans are more detailed as are many mid-distance and long distance object as well.

    In fact look from the intersection to the longest distance and the PS3 has the more smoother/uniform and detailed look.

    Even Niko himself is more pixelated on the 360 version.

    Sure the 360 version is rendered in 720p and is cleaner(up close) and sharper overall, however please don't tell me in that pic(and others) that the PS3 version does not look better.

    And i'm a major Xbox360 supporter(but not a fanboy...lol) however i have seen this in motion(both versions on a Sony 34" XBR960 in 1080i using a HDMI switch box) and the screenshots show likewise as well.

    We all know the achievements/Live/the upcoming DLC content on the 360 are no-brainers for the 360, however for graphics alone, the PS3 is the clear winner.(which is not a often occurance).

    Let's give the R* some credit here, guys. Yes they lowered the PS3 resolution to 630p and yes it appears more blurry then the 360 version(which can be fixed a bit with the in-game sliders), but the overall IQ is just plain better then the 360's.

    I don't know the details as to why(8XAF? FP16? Blur effect? higher texture quality?..ect) so and i don't pretend to, but from my two versions of GTA:IV running at the same spot/TOD, and even from all pics, it's all too obvious the PS3 version just looks better.
     
  12. Asher

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    That screenshot looks weird, everything about the 360 image looks more pixelated. Look at his face.
     
  13. Tap In

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  14. Neb

    Neb Iron "BEAST" Man
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    The xbox360 picture has easier to read sings becouse there is no blurring around the text edges making it not blend in so much with the object it is written on. Then the PS3 image has more contrast/color (TV/monitor settings/time of day/clouds?).

    The background looks better on the xbox360 one, the PS3 one has fog covering the background making it not look as good aswell making contrast with the forground IMO.

    Could this be different time of day becouse the shadow lenght is different between the 2 screenshots hence slightly different sun position (higher sun position for PS3/lower for xbox360 one)?

    Cable at window looks smother for the PS3 though.
     
    #114 Neb, May 3, 2008
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  15. Mintmaster

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    Then why are are you claiming reasons for better quality? Why are you saying there's no doubt PS3 has better AF and higher quality textures? Like I said, there's a texturing bug in the 360 version. Higher quality textures would give different results from what we're seeing.

    I think PS3 probably does have better overall quality, but it's due to Rockstar's relative apathy towards the 360 version's image quality. It's not FP16 range being more than FP10, it's not RSX allowing more AF, it's not PS3 giving a naturally warmer look, it's not BR holding bigger textures, etc.
     
    #115 Mintmaster, May 3, 2008
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  16. Dopefish

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    The 360 captures directly out of the framebuffer. So these scenes are stored in the framebuffer as 480p. So any 720p downscaling is done internally before it reaches the framebuffer. It would take some play-testing to see if there's an actual performance increase by playing in 480p instead of 720p. There are some games I've tested where they run much smoother/faster in 480p.
     
  17. Mintmaster

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    Yup, that's probably how it happens.

    The neon lights show that supersampling is happening for sure. They didn't get antialiased with 2xMSAA. The step pattern shows that the render resolution is 720p.
     
  18. Philip42

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    Mr Mintmaster,

    I never claimed that it's AF'ing or higher textures of the PS3 are using FP16, i'm only stating the overall IQ on the PS3 looks more detailed and uniform to my eye.
    (That's still with the PS3 version appearing more blurry and the 360 sharper and cleaner)

    And i agree this can easily be a texture bug on the 360, without a doubt.

    I never claimed to be an expert in FSAA/AF'ing/blur effects/FP16..ect, and i'm unsure exactly why this is happening.

    You mentioned a point in which has bothered me when i first saw this, why was the 360 rendered this way when Xenos is more powerful then the RSX?.

    And i agree if BR had held larger textures for GTA:IV, R* probably would have mentioned this.

    Seriously, does anyone here really know for sure tconcrete answers as to why?,

    Not yet.

    And this forum has some of the best minds, so maybe nobody will ever find this out.

    Now here is my opinion on this:

    Rockstar stated a 360 and a PS3 team did the rendering seperate. I just think that PS3 team took a different route, where they put some sort of post effect(blurring or any of the above mentioned) to make the textures and IQ more uniform and then added in a warmer look to it.

    The 360 version has a FPS like tone, being heavy on the blue tint, and having larger(up close) textures and and cleaner/sharper look to the game.

    As a FPS fan i was used to this style at first, until i realized what the PS3 version was attempting and how everything on screen matters more in a GTA:IV(sandbox) style game is concerned.

    And now i prefer that style, because the IQ looks uniform from up close to far away, unlike the 360 version. The 360 version maybe using more rendering up close, and drops off from the mid-long range, for all we know.

    It's too bad we can't have the combo of the cleaner/sharper look of the 360 version with the color and detail of the PS3 version.

    And from over 30 hrs of staring at both versions playing at the same time..in the same spots, i know the PS3's engine is doing something to have more detailed textures. No matter how blurry it may look..
     
  19. Philip42

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    There are just more signs more readable on the PS3 version, such as the Salon, the extra on Fabrics sign and others.

    The bricks are more uniform, the garbage dumpsters are more smooth..ect

    Yes, the larger text is more clearer on the 360 version, but it's the smaller text that is easier on the PS3.

    That's why the PS3's engine is more uniform with both the small and large signs being readable, and not just the large signs while the smaller one's get pixelated and more unreadable.

    Just look at across that street, the bricks, the garbage dumpsters, the windows, the small letters on the signs..ect, are more pixelated on the 360 version.

    Yes, the PS3 is more blurry looking, but it's also more uniform looking, which makes the scene(for me) appear more realistic.

    This really is a matter of preference(just look at all the reviews so far, and how it's still split 50/50 graphics wise), but one thing that is not preference, is that many textures are more pixelated/dithered on the 360 version, when you view them at 1X/2X/4X up close.

    Again at first i did'nt like this style, but now it makes alot of sense. Well except for it's excess blurring..

    Having said that, don't get me wrong, there are times i like the 360's engine more, and others i enjoy the PS3 style, as i really enjoy both equally.

    Anyway i'm off to sleep and then enjoying both versions, of this masterpiece. (i did too much comparing and now i need to finally enjoy this amazing game. If i don't reply back, you know the reason why :)
     
    #119 Philip42, May 3, 2008
    Last edited by a moderator: May 3, 2008
  20. Pete

    Pete Moderate Nuisance
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    Philip, though I welcome the contributions of someone who's posting (extensive) personal with the two GTA4 versions, I'm having trouble with your terminology. Though I can get the gist of your argument, and I'm willing to believe your eyes given that you say you're playing both versions back-to-back with minimized setup differences, you occasionally use seemingly contradictory adjectives to describe an effect.

    • It's puzzling to hear you say you know what AF is but later say "don't ask me why the intersection on the PS3 version is less pixelated and better filtered?" That sounds like a technical (rather than architectural--see the next paragraph) question, one that someone familiar with AF shouldn't have.
    • You say Niko looks more "pixelated" (you use that word a lot to describe rather disparate effects), but are you just referring to the aliasing (stair-stepping) on his left shoulder?
    • I could understand your last post until you threw this in: "Again at first i did'nt like this style, but now it makes alot of sense. Well except for it's excess blurring." I mean, the "'excess' blurring" appears to be the very thing that that makes the overall picture more "uniform," more cohesive, and hence more pleasing to your eye.
    • Your second to last post: though I think you and I (and most ppl here) appreciate the pros and cons of both versions, I'm slightly puzzled how you can say something is "more detailed" while at the same time "uniform" and "more blurry." (As for blanket Xenos vs. RSX statements, they're probably best left for another thread, if not another forum.) I'm not sure what "larger (up close) textures" are. Relative to the PS3 at the same distance, and taking the blur filter into consideration? To those same textures in the distance on the 360?
    And I assume when you ask if anyone's got "concrete answers as to why" the two consoles render differently, that you mean what was Rockstar's reasoning, not the actual technical reasons (which Mint and others are doing a convincing job of supplying).

    That videogamer.com shot you linked is a great example of the "painter's effect" (or stippling, dithering, etc.) that ppl say plagues the 360 version. It's evident not only in the bricks' uniformity, as you said, but in basically the entire background of that scene, from the bridge under the left traffic light to those bricks on the Movie building to the windows in the middle and right to the Nails storefront. The crosswalk lines would be an interesting test of AF, but I'm not sure how much to read into that as the sun doesn't seem to be the same intensity in both shots (the top of the traffic lights and Fabric sign, the sunlight on the corner of the Movie building, not to mention the cars, have much less intense highlights, for lack of a better word, and that might carry over into less-lit, less white, less prominent and defined crosswalk lines. I like the PS3 sshot better, more pleasing to my eye, but I don't know how much of that is due to what appears to be stronger and more diffuse sunlight (less drab) and the blur filter smoothing out the imperfections (less harsh transitions, more "uniform"), and seeing that split-screen 360/PS3 comparison vid made me think I might have a hard time dealing with the constant blurriness of the PS3 version. (But I really didn't like Quincunx or even SSAA that much on older cards for the same reason--I'll take aliased over blurry edges any day, and though the whole 360 texture issue might be as annoying, it's not evident to me in the videos I've seen [tho it's pretty obvious in sshots, as I agreed above].)

    As long as I'm nitpicking, I should point out that it's 640p, not 630p; it's blurrier, not more blurry; and I'm not yet convinced it's accurate (or advisable) to call the PS3 output "better" or the "clear winner" as opposed to "more pleasing" or "preferable." Though I get that it's a lot easier to save on the typing and let us post-process (yuk yuk) the meaning, this is the technical forum, which tries to sweat the details more than personal preferences. I'm not sure just arguing that the PS3 version is better (more successful) is the desired contribution in this particular subforum, though you're welcome to make it in a non-technical one. And for God's sake can you stop hitting the Enter key so often?! Just some things to consider if you wake up and decide you'd rather still be posting about GTA4 than playing it. :razz:
     
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