[4K Downsampling Experiments]

[K.F]

I do not agree with you

That was not an opinion.

An anti aliasing effect smooths out jagged lines by blurring/altering edges

That what post processing AA do, like FXAA, MSAA takes more actual sample, just like what the extra pixels do in down-sampling. Except it takes it where needed, instead of wasting resources on regions of the screen that does not need it like down-sampling do.

When I downsample, I yield a much higher image quality than with MSAA or other AA methods alone

If you are talking about the filtering effect on 2d textures and sprites from down sampling, then you should now it is just blurring it, I wouldn't call that a better image quality, just different. Use real filters on textures and sprites instead.

[Coornio]

[When I downsample, I yield a much higher image quality than with MSAA or other AA methods alone, so I do not agree with you. In fact, I wouldn't really consider it a true anti aliasing method. An anti aliasing effect smooths out jagged lines by blurring/altering edges. It works on these alone. Downsampling affects the entire picture, so how could that be considered an anti aliasing technique?]

It's considered an anti-aliasing technique because that is exactly what it does by definition. It takes a high resolution image with jaggies, applies down sampling and boom, you have your monitor-size frame without the jaggies anymore.

Other anti-aliasing techniques simply try to work around that due to its bigger cost and that's why you see so many different types of AA where many work better for some cases and others don't. It's all different methods to do the same thing with varying levels of success.

Personally i prefer SSAA over any other form of AA. It MAY make the textures a little blurrier because of the way it works, but frankly you hardly notice such a thing unless you specifically make a texture to make such an issue apparent. Then again, with the advent of 4K in gaming and monitors getting increasingly smaller pixels, we will reach a time when AA will be pointless simply because we can't even see the pixels with the naked eye anymore.

[dogen]

Down-sampling from higher resolution is one of the oldest and one of the worst anti-aliasing methods. Any decent AA method -like MSAA (Multisample anti-aliasing)- takes more samples ONLY where they are needed, while Down-sampling takes more samples for the whole screen whether it needs it or not. Down-sampling has its uses, since it is much easier to implement than a real AA technique.

Plenty of games(perhaps not many ps2 games) could certainly use samples in places other than polygon edges. I'll agree that it's not a very clever way of doing it, obviously some parts of the the image don't benefit at all.

[When I downsample, I yield a much higher image quality than with MSAA or other AA methods alone, so I do not agree with you. In fact, I wouldn't really consider it a true anti aliasing method. An anti aliasing effect smooths out jagged lines by blurring/altering edges. It works on these alone. Downsampling affects the entire picture, so how could that be considered an anti aliasing technique?]

Multisampling takes samples at the edges of polygons, supersampling basically does the same thing for the whole screen. Technically an image rendered with multisampling will generally have better polygon edges than a downsampled image with 4 samples per pixel, because it has a better sample pattern. For everything else the downsampled image will be superior.

[[AlexanderTheNine]]

Plenty of games(perhaps not many ps2 games) could certainly use samples in places other than polygon edges. I'll agree that it's not a very clever way of doing it, obviously some parts of the the image don't benefit at all.


Multisampling takes samples at the edges of polygons, supersampling basically does the same thing for the whole screen. Technically an image rendered with multisampling will generally have better polygon edges than a downsampled image with 4 samples per pixel, because it has a better sample pattern. For everything else the downsampled image will be superior.

[I agree that downsampling is not very convenient. I mean afterall, it requires a lot more power than even MSAA, the king of GPU hogging. I am eager to see how well Nvidia's new MFAA technology works. It's supposed to be the MSAA killer we've all been waiting for - MSAA quality with a fraction of the power requirements. When I say that I do not see downsampling as anti aliasing, I just see it as much more than that, particularly with emulators. Edges are everywhere, so it's true that Anti aliasing as a whole will pretty much make the entire screen better, but I see much more of a difference with FXAA and downsampling on PCSX2 than I do with FXAA and/or MSAA. MSAA is certainly more convenient, and with Nvidia's DSR mode, I actually find it a bit lacking right now, but it's in it's infancy, so we'll see how it progresses. I've yet to try any third party programs that force downsampling on modern games - though I do not really have the hardware to do so on modern games anyway]

[koleax]

I discovered 4K downsampling by accident one day when I set the internal res to 3840x2160 just to see what kind of frame rate I could get and whether it might be worth it to upgrade to a 4K monitor. I took some recordings to see how that would effect performance as well and when I looked back at them I thought, "wow that looks so much better than when I render at 1080p, but why? how could I be getting any benefit of 4K resolution if I don't have a 4K monitor?"

I thought there was a problem with PCSX2, honestly, that it was rendering something lower than 1080p and I had to "fix" it by setting a higher res. I posted screenshots on Twitter and someone was like, "isn't that what supersampling is?"

Anyway, yeah, you can tell I'm a noob, but damned if I'm not a huge fan of supersampling now! It just didn't occur to me that I could benefit from a higher internal resolution than my display could handle, but there I was looking at it with my own eyes before I even knew what it was.

Of course FFXII is the poster child, but games like Soul Calbur III and Tekken 5 benefit hugely as well, except for the vertical black lines at higher resolutions, which I know you're all aware of. I know the emulation development is hard, but sometimes I read that it's "impossible" to render these games higher than 1200 or 1240 pixels horizontally without those lines and I just don't believe that! There must be a way and I'm willing to help with testing or grunt work.

Check out the textures on Talim's daggers. Very refined! Lots of detail in this game and others waiting to be unlocked.

http://i.imgur.com/wNVbTUP.png
http://i.imgur.com/YaxqDXQ.png

[willkuer]

Those vertical lines are highly probable not a bug in pcsx2 but missing precision by the manufacturer namco. In native resolution this precision problem is less then one pixel. In higher resolutions is can get more than one pixel. That's why you see it.
You would probably need a game/engine depending gsdx hack to solve this black lines completely without any additional artifacts. Normally this is not the path the dev's choose because of the missing flexibility/maintainability of per game hacks.


Supersampling can be quite impressive. Unfortunately my system is a bit too weak :/

[K.F]

Those vertical lines are highly probable not a bug in pcsx2 but missing precision by the manufacturer namco. In native resolution this precision problem is less then one pixel. In higher resolutions is can get more than one pixel. That's why you see it.

So, the Namco engine just renders 10 different regions with gaps between them?

That does not seem hard to fix with a patch, yet alone impossible.

Normally this is not the path the dev's choose because of the missing flexibility/maintainability of per game hacks.

Well, even with perfect PS2 emulation, the problem would still occur when upscaled, so no way to fix it without dedicated patch. It is not a hack since it is not a workaround accurate emulation, but a direct solution to a PSCX2 specific problem.

[koleax]

Those vertical lines are highly probable not a bug in pcsx2 but missing precision by the manufacturer namco. In native resolution this precision problem is less then one pixel. In higher resolutions is can get more than one pixel. That's why you see it.
You would probably need a game/engine depending gsdx hack to solve this black lines completely without any additional artifacts. Normally this is not the path the dev's choose because of the missing flexibility/maintainability of per game hacks.


Supersampling can be quite impressive. Unfortunately my system is a bit too weak :/

I understand it might require an unconventional solution. I'm a beginner programmer, so I'd be interested even in theorizing how one might solve it.

If it's a game-level problem, and it would be too complex to solve at the emulator level, maybe we could mod the game?


My specs btw:

Mac Pro (Late 2013)
3.5 Ghz 6-Core Intel Xeon E5
16 GB 1866 MHz DDR3 ECC
AMD FirePro D700 6144 MB

I got it mostly for video editing but I also wanted to unleash PCSX2 as well and hopefully record great footage simultaneously for editing later. I can get a very smooth gameplay 60 fps at 4K but the screen capture footage runs into several bottlenecks.

Anyway here are a few more downsampled images. These are from Extreme G Racing. I'm a total sucker for Wipeout imitators and the increased res makes the environments in this game look huge.

http://i.imgur.com/Vsy5mzh.png
http://i.imgur.com/a6eP9iT.png
http://i.imgur.com/W0K3kNu.png
http://i.imgur.com/E4aL1JU.png

I still have a problem with ghosting, though. Need to figure that out. I'm using bob tff for deinterlacing and that helped considerably but not completely.

[willkuer]

So, the Namco engine just renders 10 different regions with gaps between them?

That does not seem hard to fix with a patch, yet alone impossible.

I am just guessing here but (native) pixel precise output would be the most reasonable explanation for me.

Well, even with perfect PS2 emulation, the problem would still occur when upscaled, so no way to fix it without dedicated patch. It is not a hack since it is not a workaround accurate emulation, but a direct solution to a PSCX2 specific problem.

I am not sure about this. If the problem is really what I think it is you might be able to dynamically detect missing pixel assignment for most games with the same code. Either you stretch or continue neighboring pixels/textures in that case. For namco games it seems to be one pixel beginning with 1280. I guess it is more for higher resolutions. For other games this threshold might be higher or lower.

I still think a per game hack would not be the optimal solution until you haven't even tried to find a general solution.

The only problem I see is that the general solution will be performance expensive. Automatic detecting and fixing will be hard to implement in short times. While some linear interpolation for namco games for each 100's pixel column will be easy.

---

I still have a problem with ghosting, though. Need to figure that out. I'm using bob tff for deinterlacing and that helped considerably but not completely.

Maybe better to open a new thread instead of getting support in this one.