[argyllcms] Re: Modifying internal display LUTs
- From: Graeme Gill <graeme@xxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Fri, 28 Oct 2011 18:05:04 +1100
Knut Inge wrote:
> As a side-note, most CD-players use similar techniques to offer 16 bits of
> audio quality on a 1-bit or 5-bit D/A converter. Turns out that
> D/A-converters using few bits and dithering/noise shaping can be made better
> and cheaper than direct 16-bit ones. Perhaps the same is the case for LCD
> displays (the 9th and 10th LSB is relatively unimportant, is it not?)
Right, but they combine it with over sampling to get an effective
16 bit or better resolution over audio bandwidth. The visual equivalent
would be to use higher resolution displays and trade the extra
spatial resolution for level resolution. They don't do that. What
they do instead is more analogous to 8 bit audio dithering, where
the dithering is in the hearing range, and the result it
a very audible hiss that may be better than straight 8 bit quantization.
> True, but companies such as Entech and open-source communities such as
> ddccontrol seems to have a lot of knowledge, even about proprietary
> signalling
> http://entechtaiwan.com/
I don't see any source code there, or any other technical information.
> http://ddccontrol.sourceforge.net/
I'm told this project is pretty quiet.
> There seems to be hints that even less high-end manufacturers (like Dell)
> may have sort-of accessible LUTs that they choose to not reveal. One
> argument is that there seemingly are only 2 or a few manufacturers of
> display controllers out there.
Even if that's the case, then unless they document it, or unless
there is a utility that can exercise it, it's pretty hard to figure
out how to driver it.
> Again, true. I have a Dell display that can accept 10-bit over Displayport,
> and ATI-cards seems to have supported 10-bit in some form for ages. But your
> application needs to use OpenGL to access it (at least on Windows), and
> Lightroom does not do that.
You're confusing frame buffer with LUT. There has been 10 but LUT support
for some time.
cheers,
Graeme Gill.
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