Re: ociobakelut clamps tops?


dbr/Ben <dbr....@...>
 

You'll need to use the --shaperspace to make a LUT that goes from a non 0-1 space, otherwise you trying to do a lin-to-log in a 3D LUT.

If I understood the code right, it does..

CSP prelut: input to shaperspace as 1D LUT
3D LUT: shaperspace to output space

If omit the shaperspace arg, then it's all done in the cube (and the prelut is a no-op)

...so I think your display colourspace needs to have a 0-1 log input (just the kodak LUT). Then you would do:

--inputspace graded_linear --shaperspace jplog --outputspace kodak2383_dreamcolour

Not ideal, although you could possibly do the grade in the dreamcolor space by doing a log2lin, CDL then lin2log, and replace the graded_linear space with your scene_grey18

Ideally the Baker would inspect the transform op-tree and put as much of the 1D transform (the CDL and lin2log parts) in the prelut, and the rest in the cube.. Not sure how difficult this would be to achieve (think there's todos in the code about this)

- Ben

On 29/04/2011, at 2:56, Jeremy Selan <jeremy...@...> wrote:

Hmmm,

Oliver - could you email be your jp_lin2log.lut (directly)? I'd like
to re-create this on my end. Dont worry about the Kodak cube lut, I
can use one of my own there instead.

One thing I notice, the Dreamcolor family shouldnt be 'lin'. I'd
probably set it to 'Dreamcolor' on the absence of other information.
(The family is often used to short-circuit conversions of the same
type, but at differing bit depths). I should probably update the API
so people can leave it blank if they dont know it, and to assume the
color-space name in that case).

-- Jeremy

On Thu, Apr 28, 2011 at 1:20 AM, Oliver Farkas <oliver...@...> wrote:
Hey guys,

I'm trying to use ociobakelut to bake out a .csp lut. I'm using the latest
opencolorio (0.8.0), but getting weird results. It clamps the tops, details
in the bright areas are completely gone. I'm wondering if I'm missing
something.


The command I'm using is this:

ociobakelut --iconfig ./config.ocio --inputspace scene_grey18 --outputspace
Dreamcolor --format cinespace > ./Kodak2383CoolGrade_ocio_Dreamcolor.csp

The corresponding parts in the config.ocio look like this:


- !<ColorSpace>
name: scene_grey18
family: lin
bitdepth: 32f
isdata: false
gpuallocation: lg2
gpumin: -15
gpumax: 6


- !<ColorSpace>
name: Dreamcolor
family: lin
bitdepth: 32f
isdata: false
gpuallocation: uniform
gpumin: 0
gpumax: 1
from_reference: !<GroupTransform>
children:
- !<CDLTransform> {slope: [0.80369623146242275, 0.9566818354009814,
0.94751600781483858], offset: [0, 0, 0], power: [1, 1, 1], saturation: 1}
- !<FileTransform> {src: jp_lin2log.lut, interpolation: linear}
- !<FileTransform> {src: Kodak2383_Dreamcolor.cub, interpolation:
linear}



Cheers,
Oliver

Join ocio-dev@lists.aswf.io to automatically receive all group messages.