confused on HDR + AA

[tony4704]

Im making my decision atm on which card to get and I dont understand the stuff about HDR and AA. So ATI can do both at the same time and NV can only do either or?

What exactly is HDR? Where can I search to find games and which settings they need so that I can determine which card to get for which games need the features? thank you

 

[Gamer X]

I got the same question,can someone enlighten us please ?

 

[Munky]

Originally posted by: tony4704
Im making my decision atm on which card to get and I dont understand the stuff about HDR and AA. So ATI can do both at the same time and NV can only do either or?

The short answer is Yes. The long answer is it's up to the developers of the game. Nv cant do FP blended HDR + MSAA at the same time. These are the most common methods of HDR and AA. However, HDR can also be done through the pixel shaders, as in Lost Coast, in which case it has no affect on AA ability, but it's only used in Source-based games. Also, the developers can manually program SSAA into the game engine, like in AOE3, which will allow Nv cards to run HDR with AA but at a much higher performance penalty. Other games, such as Farcry, Chaos Theory, and Serious Sam 2 use FP blended HDR and MSAA , and thus will not run with HDR and AA on NV cards. (Chaos Theory, however, does not allow HDR + AA at the same time, but with an appropriate patch it should work on the x1k cards)

What exactly is HDR? Where can I search to find games and which settings they need so that I can determine which card to get for which games need the features? thank you

HDR stands for high dynamic range lighting, and is used to more accurately model lighting based on the real world. Compare the two screenshots here:
http://www.behardware.com/articles/605-...0-xt-and-x1900-crossfire-in-tests.html

 

[moonboy403]

hdr = high dynamic range

it's a kind of lighting effect which creates more realism

games such such hl2 lost coast and far cry have such feature

as for hdr + aa....ati can do it anyhow

but for nvidia, they can only do both when the developer implement such feature in the game due to hardware limitation
otherwise, you only only use either hdr, or aa in the game

 

[Matthias99]

Originally posted by: tony4704
Im making my decision atm on which card to get and I dont understand the stuff about HDR and AA. So ATI can do both at the same time and NV can only do either or?

Basically.

What exactly is HDR? Where can I search to find games and which settings they need so that I can determine which card to get for which games need the features? thank you

HDR is High-Dynamic Range (Rendering); in a small nutshell, it allows for a larger range of brightness values in a rendered scene, producing potentially more realistic images. If you have a card capable of running SM2.0 or better (RADEON 9XXX or GeForce FX or better), and own HL2, download the Lost Coast demo to see it for yourself.

There are several ways of doing this; the Source engine (the one HL2 uses) can do HDR through pixel shaders; a few other games can use OpenEXR floating-point framebuffers. Any SM2.0 or higher card can do HDR through shaders; only the GF6, GF7, and R520/R580-based cards can do OpenEXR HDR.

The following games support HDR rendering:

Far Cry (w/ 1.3 patch) -- OpenEXR
Splinter Cell: Chaos Theory -- OpenEXR
Serious Sam 2 -- OpenEXR
Age Of Empires 3 -- OpenEXR
HL2: Lost Coast (tech demo) -- Shader
Day of Defeat: Source (HL2 mod) -- Shader

I think that's it for the moment. A bunch of upcoming games (the next UT, ES: Oblivion, and STALKER to name a few) are supposed to support it as well.

Edit: Stupid smiley. Also added AOE3 to list of games.

 

[imhungry]

[edit]

nevermind, fifty people answered at the same time.

HDR is High Definition Range (Lighting). (Makes games like Far Cry and Half Life 2: Lost Coast look even more beautiful)
AA is Anti-Aliasing, which straightens out pixels and edges.

Currently, AFAIK, Nvidia doesn't support the simultaneous use of HDR and AA, only one of the two at a time. The ATI cards (7900 vs 1900) support this HDR+AA use.

I would just use a high resolution + HDR seeing that you have that 7800GT.

 

[Jules]

So the 7900gtx cant do HDR+ AA?

 

[Inappropriate4AT]

Frankly, I think HDR looks like crap. I always turn it off.

 

[tony4704]

ok i will download that demo, thanks all appreciate it.

Is that the only real difference between these cards features, besides AVIVO? or doesn't ati do some other kind of AA or AF that NV doesnt?

 

[moonboy403]

ati does angle independent af which is superior to what nvidia has to offer

nvidia's card consume less power and thus produces less heat (quieter cooler too)

ati has avivo while nvidia has purevideo

 

[Wreckage]

Originally posted by: MyStupidMouth
So the 7900gtx cant do HDR+ AA?

Yes and No.

It can't do it using the OpenEXR method of FP16 HDR.

But the HL2/DoD:S method using shaders the 7900 can do HDR+AA

 

[otispunkmeyer]

it cant do the FP16 HDR and multi sample AA(as used in far cry and possibly splinter cell 3? ... i know they grey it out when you turn HDR on) though there is apparently work arounds...like using supersample AA, but im willing to be the performance is an abomination to speed.

it is,however, quite capable of doing HDR and AA when the HDR is being processed in the pixel shaders (unlike openEXR's FP16) and this can be seen in the lost coast tech demo.

ATI currently have the only hardware capable of HDR and AA (multisample) whilst using FP16HDR