# What are the different types of Anti-Aliasing?



## jasper1605 (Mar 19, 2010)

I've been trying to read on wikipedia what the differences are between anti-aliasing and such like MSAA QSAA or other kinds like what I see in the options on Left For Dead 2.  Unfortunately, it gives me a history and calculus lesson before it tells me the answer.  

About all I know is that AA is for softening images to reduce jaginess, but that's as far as my comprehension goes; can anyone explain further what it means?

Also, sorry if this is in the wrong section, I wasn't sure where a good place to put this (or even search for it) would be.


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## Munki (Mar 19, 2010)

Im curious as well. I haven't done any research other than to figure out why COD 2 and mu 9800 GT were having a civil war givin' me a gray screen.


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## jasper1605 (Mar 19, 2010)

seems like civil wars like to happen often within computers.  That tweak itch that we all get just forces us to change things even if we know it's working perfectly just to see if it can push a little bit farther, lol.


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## pantherx12 (Mar 19, 2010)

Wikipedia explains it great

http://en.wikipedia.org/wiki/Anti-aliasing

FSAA ( full screen anti aliasing) is what is done over 3d games so scroll to that in particular.


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## Nailezs (Mar 19, 2010)

thanks panther, very intersting


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## jasper1605 (Mar 19, 2010)

but what's the difference between things like msaa qsaa etc... ???


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## Techtu (Mar 19, 2010)

jasper1605 said:


> but what's the difference between things like msaa qsaa etc... ???



I believe each has it's own method in which way it codes the AA (anti Aliasing).


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## pantherx12 (Mar 19, 2010)

Had no idea, so I googled.

This forum post makes sense to me

"Let's put it another way. 16x QSAA would give you the same level of edge anti-aliasing as 16x MSAA, at the same cost as 8x MSAA. The trade-off is that textures will become blurrier, making 16x AF look like 4x AF.

MSAA is the quality option, QSAA is the speed option. In things like racing games, where you are moving too quickly for slight texture blurring to matter, but aliasing is super-apparent, then QSAA is a great choice. In something like Borderlands, where the unique texturing is a huge feature of the game, then QSAA is a crappy choice.

"


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## Techtu (Mar 19, 2010)

pantherx12 said:


> Had no idea, so I googled.
> 
> This forum post makes sense to me
> 
> ...




I didn't know the actual difference, although I did have something kind of like that in my head, so thank's for the input


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## douglatins (Mar 19, 2010)

My control classes are teaching me AA in common signals and fuctions and the application is the same in games, but rather a dot matrix


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## Trigger911 (Mar 19, 2010)

pantherx12 said:


> Had no idea, so I googled.
> 
> This forum post makes sense to me
> 
> ...


+1 I didnt know myself now I do


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## TheLaughingMan (Mar 19, 2010)

I am not sure but I do know two things that may help you find more info.

MSAA = Multisampling AA
QSAA = Supersampling AA

The primary difference is the algorithm used.  As stated, one (Super) is the quick and dirty AA which is why it is much faster and lighter on video card.  Multisampling is the "measure twice, cut once" principle.  The algorithm takes, as implied (several samples of the image) to ensure accurate location when the output is done.  The result is cleaner and less jaggy, but at the cost of additional process time.


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## jasper1605 (Mar 19, 2010)

thanks much for that description panther!
Exactly what I was wondering


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## pantherx12 (Mar 19, 2010)

We can thank "darklordjames" of the AVS forums for the original post XD


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## Polarman (Mar 19, 2010)

This could be helpfull too.

http://www.xbitlabs.com/articles/video/display/gf8800_14.html


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## daehxxiD (Mar 20, 2010)

QSAA is not supersampling. I think it is Nvidias own technique called "Quincunx" available since the Geforce 3 (?). What this does is give you the double the edge-smoothing at an expense of texture-definition but not of speed. So actually what reads as 16x QSAA is very likely 8x Quincunx AA; like what in geforce 3 times was simply called 2x Quincunx-Antialiasing (which was basically in between 2xMSAA and 4xMSAA).

Supersampling on the other hand is a very high-quality Antialiasing method, that also anti-aliases alpha-blended textures (like fences and stuff).

Very simply put.


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## qubit (Mar 20, 2010)

Because frame rate is important above all else for me, especially in a twitchy fps, I turn AA off and just use AF, usually at x16. I find that the jaggies are not all that objectionable to me most of the time and the frame rate is much better without AA.

I like a solid 85Hz refresh with no dropped frames on my CRT monitor (or 120Hz on Samsung LCD 2233RZ monitor) at a decent resolution and can usually achieve that on modern games on my hardware, which is fairly high end. Heck, I paid enough for it...


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## daehxxiD (Mar 20, 2010)

qubit said:


> Because frame rate is important above all else for me, especially in a twitchy fps, I turn AA off and just use AF, usually at x16. I find that the jaggies are not all that objectionable to me most of the time and the frame rate is much better without AA.
> 
> I like a solid 85Hz refresh with no dropped frames on my CRT monitor (or 120Hz on Samsung LCD 2233RZ monitor) at a decent resolution and can usually achieve that on modern games on my hardware, which is fairly high end. Heck, I paid enough for it...



Personally I think AA is one of the most Picture-Improving techinques possible. Games nowadays almost look like CG in some cases and it's only the Aliasing that give it away as Realtime. So enableing AA in some Cases really helps; a lot.

With Crysis for example, I also think that the boost in quality is not worth the Performance hit, but in other games AA doesn't cost all that much anymore and at >1Megapixel even 2xAA makes a world of diffrence.


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## qubit (Mar 20, 2010)

Dixxhead said:


> Personally I think AA is one of the most Picture-Improving techinques possible...



Absolutely - AA can make a big difference. The type and specific game you play, your hardware and your preferences all come into it. The effect of using or not using it is very subjective to a large extent, so there's no right or wrong to this.

In a fast game like Unreal Tournament 2004, where every millisecond and every frame can mean the difference between fragging or being fragged, picture quality comes second to a rock solid, vsynced frame rate, but the compromise doesn't have to be very much with today's hardware. Also, you get much better lag performance and lack of motion smear on a CRT, so I keep a couple just for games.


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## Mussels (Mar 20, 2010)

new thread title. This one actually asks the same question as your post, not a different one.


IIRC

MSAA blurs the colors between 'pixels', to make the edges softer.

SSAA (super sampling) actually renders the scene at a higher resolution then shrinks it.


Nvidias "Q" AA modes are mostly marketing crap, it tends to mean "we turned the performance cheats off in this mode, so it looks a little better"


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## jasper1605 (Mar 21, 2010)

thank you mussels


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## pantherx12 (Mar 21, 2010)

Mussels is wrong by the by MSAA is multisampling an optimised version of Super Sampling it AAs the edges of the polygon but won't really bother with anything else so you can get artifacts inside the polygon still.


"The term generally refers to a special case of supersampling. Initial implementations of full-scene anti-aliasing (FSAA) worked conceptually by simply rendering a scene at a higher resolution, and then downsampling to a lower-resolution output. Most modern GPUs are capable of this form of antialiasing, but it greatly taxes resources such as texture bandwidth and fillrate. (If a game is highly TCL-bound or CPU-bound, supersampling can be used without much performance hit.)

According to the OpenGL GL_ARB_multisample specification, "multisampling" refers to a specific optimization of supersampling. The specification dictates that the renderer evaluate the fragment program once per pixel, and only "truly" supersample the depth and stencil values. (This is not the same as supersampling, but by the OpenGL 1.5 specification, the definition had been updated to include fully supersampling implementations as well.)

In graphics literature in general, "multisampling" refers to any special case of supersampling where some components of the final image are not fully supersampled. The lists below refer specifically to the ARB_multisample definition."


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## Mussels (Mar 21, 2010)

hey i said 'iirc'  - if i recall correctly


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## pantherx12 (Mar 21, 2010)

Ah right, I didn't know that iirc meant that


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## TheLaughingMan (Mar 21, 2010)

AA, turn that $#^( ON as high as your card can handle.


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## pantherx12 (Mar 21, 2010)

TheLaughingMan said:


> AA, turn that $#^( ON as high as your card can handle.



This is probably all you really need to read in this thread


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## EastCoasthandle (Apr 9, 2010)

*Traditional, Hardware Specific and Post Processing AA*

Hmm lets see...
There are several different types of AA that can be used/seen in games today.

Quincunx AA  - Sometimes used on PS3 instead of MSAA.  Uses 2 geometry sample points just like 2xMSAA, but it also uses 3 samples belonging to neighboring pixels.  This results in blurring.    
Examples:
Quincunx
vs
MSAA

-SSAA - Super Sampled AA
-MSAA - I think we all know what this is
-Transparent AA - NVIDIA for Alpha textures, etc
-Adaptive AA - AMD for Alpha textures, etc

*Nvidia's CSAA *- Coverage sampled AA.  Used to increase frame rate by using a reduce number of coverage samples normally found in MSAA.  This is typically mistaken by some as MSAA when infact it is not. IE: "I can use 8xAA in games" can be misleading when in fact that person is using 8x CSAA.  If they were using true 8x MSAA it should read 8xQ (or whatever they are using now). CSAA is found in some games along with MSAA.  

*CSAA in Color, Z and Coverage*

2x....= MSAA (1, 2, 2)
4x....= MSAA (1, 4, 4)
.....
 8x...= CSAA (1, *4*, 8)
8xQ = MSAA (1,*8*, 8)
.....
16x..= CSAA (1, *4*, 16)
16xQ = CSAA (1, *8*, 16)

*ATI's CFAA* - Custom-Filter Anti-Aliasing that takes samples from "outside the pixel boundary".  It provides more samples per pixel than MSAA without any real impact on the memory footprint.  They can work alongside floating-point blending based High Dynamic Range rendering and anti-aliasing stencil shadows.   The draw back to Narrow and Wide Tent is blurring.    Edge Detect performs a pass to discover any edges on the rendered scene, resolving those edges only (if I recall correctly).  This is done by using AA while the rest of the image is AA'd using a standard box filter and a lower number of samples.  If my memory recalls correctly you want to use either 8xAA (or higher) or Edge Detect you want to overclock the GPU in order to increase the Shader Clock to reduce the additional performance penalty using them.   


*Mode          	Filter *

2x, 4x, 8x Box = Normal AA
4x CFAA	 2x + Narrow tent
 6x CFAA	 2x + Wide tent / 4x + Narrow tent
 8x CFAA	 4x + Wide tent
 12x CFAA	 8x + Narrow tent / 4x + Edge detect
 16x CFAA	 8x + Wide tent
 24x CFAA	 8x + Edge detect

There is one more called Analytical AA which I believe is something similar to adaptive AA algorithm.  But haven't found a whole lot about it.

There is also deferred rendering and forward rendering: MSAA, FSAA, AAA, etc algorithms


*Practical Morphological Anti-Aliasing*
Recently, I've come across another AA method called *Practical Morphological Anti-Aliasing* (MLAA).  This type of AA appears to be used most with Sony (GOW III, KillZone 3, etc) and it appears to have originated from Intel according to this article.  The quality of MLAA is between 4xAA and 8xAA MSAA at a fraction of the memory and time consumption.  Because this process works as a  post-processing it should work with any game.  How it works is by detecting specific patterns in color or depth information of boarders and anti-aliasing them by blending pixels of those borders according to the type of pattern and position they belong to within the pattern.




MLAA





8xAA





1xAA

Take notice of the railing in the upper right corner. And here is another article another article about MLAA.


*Directionally Localized Anti-Aliasing*  This will be found in DLAA in Force Unleashed II (link demonstrates DLAA vs no AA).  DLAA is similar to MLAA but little is explained as to how it works at this time.  Current execution times for DLAA are:
"Xbox 360: 2.2 +/- 0.2ms @ 1280x720
"PlayStation3 (5 SPUs): 1.6 +/- 0.3ms @ 1280x720"


> [DLAA (Directionally Localized Anti-Aliasing) - our custom anti-aliasing algorithm implemented in Star Wars : The Force Unleashed 2. In terms of picture quality it is comparable with MLAA, but due to perception based probabilistic nature it features high temporal stability and implemented on both the GPU (X360, PC) and PS3 SPUs ]



Below are some examples of DLAA vs no AA.  





















There is also Directionally Adaptive Edge AA. But I've not seen it in games yet.


Nvidia's Version
SRAA 
FXAA

Fear 3 uses FXAA below are examples of what FXAA looks like vs 4x MSAA.

FXAA example
vs
4xMSAA
Take notice of the grating on the crate.


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## jasper1605 (Apr 9, 2010)

Those last 3 posts are an awful lot more info about AA than I ever thought I'd even hear about lol


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## Mussels (Apr 9, 2010)

jasper1605 said:


> Those last 3 posts are an awful lot more info about AA than I ever thought I'd even hear about lol



dun worry, they're one post now


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## Zubasa (Apr 9, 2010)

Edge Detect is the only CFAA mode I use apart from the good old MSAA/SSAA aka box.
The other 2 modes I only use them once in a while when I was still gamming on my 4850.

The best thing about the new HD5k series is that they finally have a slider to chose between SSAA and MSAA or adapative.


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## jasper1605 (Apr 9, 2010)

Mussels said:


> dun worry, they're one post now



Thanks Mussels, I thought my mind was going to melt for a second.  It's much safer for the world now that the info has been compiled into one post


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