Is HDR "Free" for the Xenos?

That's something that concerns me actually. A recent MS post had some bloke talking about minimum requirements, and they mentioned '16x9'. I haven't heard anything about 4:3 output on any platform
 
Well 720p is by definition a widescreen resolution. You shouldn't be able to get a 720p 4:3 image, as there aren't that many TVs out that are HD but not widescreen. If any at all.

One could wonder about PC monitors though, hardly any are widescreen, so in case the consoles can be hooked up to PC monitors, the image would be letterboxed. That's my guess anyway.
 
london-boy said:
Well 720p is by definition a widescreen resolution. You shouldn't be able to get a 720p 4:3 image, as there aren't that many TVs out that are HD but not widescreen. If any at all.

Over the last couple years I have seen a lot more widescreen TVs, non HD, sold in the US. In the past a there were large screen TVs were widescreen, and now they even have CRT wide screen SDTVs. They are something like 853*480.

Granted, they are not the majority, or even something I would worry about as as dev (less allowing 720p to scale 1:1 aspect to these sets), but always an option.

One could wonder about PC monitors though, hardly any are widescreen, so in case the consoles can be hooked up to PC monitors, the image would be letterboxed. That's my guess anyway.

I hope they are letterboxed on the PC! :D You sit a couple feet from the monitor, so it is not that bad. And I much prefer widescreen gaming!
 
I've only heard that in the form of rumors/speculation. MSAA+HDR isn't supported on G70 for a reason. It's mathematically stupid for reasons not the least of which is because you don't use HDR for purely rendering reasons; you use it for further calculations -- looking "visually acceptable" isn't good enough. Never mind floating point issues when you can potentially have edge deltas that are several orders of magnitude apart. MSAA is noise-prone.
 
ShootMyMonkey said:
I've only heard that in the form of rumors/speculation. MSAA+HDR isn't supported on G70 for a reason. It's mathematically stupid for reasons not the least of which is because you don't use HDR for purely rendering reasons; you use it for further calculations -- looking "visually acceptable" isn't good enough. Never mind floating point issues when you can potentially have edge deltas that are several orders of magnitude apart. MSAA is noise-prone.

Wasn't that full auto game confirmed to have both HDR and MSAA?

In the thread that asks this question, Dave linked his article and locked the thread. I think this is the relevant bit.

The ROP's can handle several different formats, including a special FP10 mode. FP10 is a floating point precision mode in the format of 10-10-10-2 (bits for Red, Green, Blue, Alpha). The 10 bit colour storage has a 3 bit exponent and 7 bit mantissa, with an available range of -32.0 to 32.0. Whilst this mode does have some limitations it can offer HDR effects but at the same cost in performance and size as standard 32-bit (8-8-8-8) integer formats which will probably result in this format being used quite frequently on XBOX 360 titles. Other formats such as INT16 and FP16 are also available, but they obviously have space implications. Like the resolution of the MSAA samples, there is a conversion step to change the front buffer format to a displayable 8-8-8-8 format when moving the completed frame buffer portion from the eDRAM memory out to system RAM.

The ROP's are fully orthogonal so Multi-Sampling can operate with all pixel formats supported.

I think that last bit confirms HDR + MSAA. FP10 being one of the pixel formats, right?
 
ShootMyMonkey said:
Xenos uses MSAA, which increases the number of samples, not pixels.
Only if you don't use HDR.

Dave's Excellent Xenos Article At B3D that has been available for a month now said:
The ROP's are fully orthogonal so Multi-Sampling can operate with all pixel formats supported.[Edit: Which in context is clearly both FP16 and FP10]

http://www.beyond3d.com/articles/xenos/index.php?p=04

This has been known for a month--Xenos can do FP16 or FP10 with MSAA.

G70's HDR issues have no bearing on R500 (or R520 for that matter). It all comes down to where NV and ATI want to spend their transistor budget.
 
Shifty Geezer said:
That's something that concerns me actually. A recent MS post had some bloke talking about minimum requirements, and they mentioned '16x9'. I haven't heard anything about 4:3 output on any platform

They talk about it here:

Paul: Is it scaling down to the same aspect ratio? Or is it scaling it down to 4:3?

Jeff: We will actually give the game developers a choice. They can either have the Xbox 360 automatically crop or scale. Or, they can render a different aspect ratio scene of their game if they want to. Or, a game developer can say, "let the user choose." And there will actually be a setting in Xbox 360 to tell the box what it should do. And game developers can just hand it over to the box to decide what's best from a user's perspective.

http://www.winsupersite.com/showcase/xbox360_inside.asp
 
Hm... Interesting. I wonder if it's just the devkits that don't support it then. There was something going on a few days ago with AA costing us a 3:1 drop in framerate and which wasn't there when disabling the HDR passes. Might have just been an FP32 thing -- I'm really not up to date on what's going on with that particular team, but the profiles one of them showed on his daily updates show pretty clearly being limited on the beta kits with AA enabled in any form. That basically makes me think there's no way in hell it can be free... that and the whole "free lunch" thing.
 
ShootMyMonkey said:
Hm... Interesting. I wonder if it's just the devkits that don't support it then. There was something going on a few days ago with AA costing us a 3:1 drop in framerate and which wasn't there when disabling the HDR passes. Might have just been an FP32 thing -- I'm really not up to date on what's going on with that particular team, but the profiles one of them showed on his daily updates show pretty clearly being limited on the beta kits with AA enabled in any form. That basically makes me think there's no way in hell it can be free... that and the whole "free lunch" thing.

I thought the question was whether HDR + MSAA was possible. I have no idea what it costs performance wise.
 
I thought the question was whether HDR + MSAA was possible. I have no idea what it costs performance wise.
If that big a hit was seen for AA on HDR, then I'd have to doubt MSAA was possible. Again, it may be a devkit thing or a no MSAA + FP32 thing (don't really know what they use). If it was SSAA only, the cost would have made perfect sense.

I know there was stuff that suggested it, but I make a habit of never believing anything I read... unless it's all bad news (as if there's any other kind :rolleyes:). So I'm a cynic. So sue me.
 
ShootMyMonkey said:
Hm... Interesting. I wonder if it's just the devkits that don't support it then. There was something going on a few days ago with AA costing us a 3:1 drop in framerate and which wasn't there when disabling the HDR passes. Might have just been an FP32 thing -- I'm really not up to date on what's going on with that particular team, but the profiles one of them showed on his daily updates show pretty clearly being limited on the beta kits with AA enabled in any form. That basically makes me think there's no way in hell it can be free... that and the whole "free lunch" thing.

If you are associated with a development house I would suggest a few things:

1. Don't make comments like "Console X cannot do feature B" without being sure first. People look up to those on the inside and there is enough FUD out there.

2. Be careful with what you say. You give a pessimistic conclusion ("no way in hell" is pretty opinionated) yet admitt having very little insight into that team. You could ASK them ;) But you, of all people, should know in development that there are all kinds of bugs that can reduce performance when a feature is enabled that, in the final product, is not an issue at all.

Not trying to be a jerk about it, but you came off pretty authoritative on the FP16+MSAA comment and it appears from the information ATI has verified that it infact does. Like I said, people look up to devs and insiders. Seeing as you are on the inside we probably want to leech a LOT of good info off you. :D But as they say, "With great power comes great responsibility".

So if you can get us some verified info I am sure someone would sell a kidney to get the scoop ;)
 
ShootMyMonkey said:
I thought the question was whether HDR + MSAA was possible. I have no idea what it costs performance wise.
If that big a hit was seen for AA on HDR, then I'd have to doubt MSAA was possible. Again, it may be a devkit thing or a no MSAA + FP32 thing (don't really know what they use).

Code be a code issue, could be a devkit issue.

But it could be just a fact of life that Xenos may not be able to do MSAA & FP16 at a good framerate. (I do not believe it supports FP32).

Now THAT is entirely possible. We saw how NV40 performed poorly with FP16 alone, so the chip may not be designed around doing FP16 w/ MSAA at reasonable framerates. It does seem FP10 is the desired sweet spot.

Now go ask them whats up so you can give us all the juicy details! ;)
 
you came off pretty authoritative on the FP16+MSAA comment
Actually, I never really thought about it in terms of FP16/FP10/FP32 or whatever. HDRIE was the last thing I worked on involving HDR, so I always just assume HDR == either 128-bit float4 or RGBE... and I never liked RGBE. Force of habit.

It's odd that there would be a significant drop with FP16 + MSAA, but not so much with FP16, though. But then again, it's not like I can't say that there's nothing in 360 that screams out MS dropped the ball. Any more than I can say there's nothing in PS3 that screams Sony dropped the ball.

Now go ask them whats up so you can give us all the juicy details!
I'm not telling you what project it is, if that's what you're wondering. It'll be a while before that happens. It'll also be a good few months before I get a devkit on my desk. Although I wouldn't be surprised if a PS3 devkit showed up before we got that far.
 
ShootMyMonkey said:
Now go ask them whats up so you can give us all the juicy details!
I'm not telling you what project it is, if that's what you're wondering. It'll be a while before that happens. It'll also be a good few months before I get a devkit on my desk. Although I wouldn't be surprised if a PS3 devkit showed up before we got that far.

We can wait on a game title... gimmie some juice on the hardware :LOL: You know most of us spend time here posting instead of playing games ;)

Good luck on the new project... and maybe we can have a "B3D day" where we can come see the dev kit on your desk. We promise not to drool... much ;)
 
Well, I can say this much from what I see so far. Everything that people expected to be god-awful (e.g. memory latency) has so far shown to be a tiny bit (less than 5%) worse than expected.
 
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