future of hdr colorspaces

[Boudewijn Rempt]

On Friday 01 June 2012 Jun, Simon Legrand wrote:

> Lol. Yes, we do have plenty or ram. However we're dealing with such high
> resolution textures most of the time that even our massive amount of ram
> needs to be saved and used wisely. (64Gb in my current
> machine<http://h10010.www1.hp.com/wwpc/us/en/sm/WF06a/12454-12454-296719-307907-4270224-3718645.html?dnr=1>
> )

I'm jealous!

> ILM and NVIDIA more or less pioneered 16bit half for memory reasons and
> it's become standard for us in almost all case except extreme displacement
> maps which sometimes require 32bit grayscale.
> 

The good thing is that Marti has all but decided to support half in the next release of lcms2 after I and Kai-Uwe asked for it again. So that shows a good path forward :-)


> That said. This discussion should be all about performance. I've no idea
> what effect OpenColorIO would have on both the performance and initial
> stability, and neither do I really know how much work it would involve to
> implement.
> 
> What Krita offers now is very promising so if you thin it is possible to
> stick with what's currently available and refine it then I would prioritise
> that.

I really need to dig in, but Krita can actually support multiple color engines concurrently. Krita is also a bit weird compared to other application in that we offload almost all color manipulation, including things like levels filters to the color engine -- and those engines are plugins. We have/had a couple already:

lcms1
lcms2
ctlcs
and, sort of, the painterly colorspace engine

I guess we could just add another one... But the ocio docs are really limited.

> 
> I'm in the process of making templates of our most commonly used image
> formats and bit depth, which I will send to Boudewijn tomorrow.
> 
> But just to give a rough idea, we're almost never painting in 8bit and
> under 4096x4096.
> 
> Usually we're looking at images of 8192x8192 at 16bit.

Float, right?

> Trying it at home with the latest and greatest everything (kubuntu 12.04
> and krita 2.4 straight out of apt) the performance is actually very good.
> Definitely usable without much trouble. I have tried all the filters brush
> ect yet, but it seems great to me.
> 
> The tarball I'm using at work is not cutting it as easily at those
> resolution but that's simply because it's a 32bit build. Boudewijn said he
> was working on a 64bit build for us so I'm impatiently waiting for it to
> start benchmarking against the photoshop box that sits next to me. :)

Good point... I'll also compile the 64 bits version with more optimizations and less debug. The 32 bit build was very experimental.


> 
> And I'm rambling again.
> 
> 
> >
> > --
> > Cyrille Berger
> > _______________________________________________
> > kimageshop mailing list
> > kimageshop at kde.org
> > https://mail.kde.org/mailman/listinfo/kimageshop
> >
> 
> 
> 
> 


-- 
Boudewijn Rempt
http://www.valdyas.org, http://www.krita.org, http://www.boudewijnrempt.nl