[Openicc] Helping with colord

[Richard Hughes]

On 9 March 2011 10:11, Chris Murphy <lists at colorremedies.com> wrote:
> There's got to be an intermediate position that's workable

Sure, of course.

> For the devices that report bogus EDID, the code that's building the profile needs to do some checking for rational primaries with some tolerance. A yellow x,y value for green isn't sensible. Negative values aren't sensible. Etc.

Yes, I suppose that's sensible, although I generally dislike heuristics.

> And a major missing link persistently with camera JPEG is ignorance of EXIF color space.

Yup, GCM has a toy-API where you can give it a filename with path and
it'll spit out a suitable icc profile filename. To assign the EXIF
data to a profile, you just drag and drop the .jpg file into GCM and
it creates a virtual device using the data from the EXIF tag. From
there you can assign it a suitable profile. It's kinda a gimmick, but
at least I know it's now possible.

> That parent could be a device attached to my computer

My use case for this is I have a virtual device called "Photo printing
shop on High Street" which I have assigned profiles for. It's kinda
useful to see what the photo is going to look like (poor mans
prepress) and is certainly better than nothing. It's by no means the
ideal workfow for this kind of operation, I know.

> This cannot be the first time this has been thought of. There must be other specs or projects elsewhere that are dealing with this same issues and we should simply adopt what's common.

I don't believe so. It kinda has to be a bit domain-specific due to
the use-case.

> A web cam is an interesting issue. Video is interesting. Complex.

I talked with the GStreamer guys about this at GUADEC last year. They
were very keen to do something GStreamer specific (as a pipeline
element) and just get the profile from GCM / colord. I explained to
them that I think color correcting video is a bit harder than just
applying a ICC transform on every frame of the video. It's perhaps a
first step tho. It's not really my area of expertise.

> But still there needs to be a mechanism for competing proposals to be formally presented, debated and then something decided upon.

I think debate of design decisions is a totally good thing, but I'm
not sure debating every little part of a perfect specification before
implementation is a good use of anybodies time. If Kai-Uwe turned
around to me and said "hey, can you prefix all your display device
ID's with 'display_' rather than 'xrandr_' and also include the serial
number" then that's constructive. At the moment we're not having
anywhere near that kind of dialog.

Richard.