Re: Reference !<Colorspace>


Malcolm Humphreys <malcolmh...@...>
 


I don't see that the reference space should be separate in the profile. It's important, but it is just a role.
 
Is it just a role? seems like each colorspace needs it to convert between each other. Roles main purpose is to have abstract names / pointers for colorspaces. The reference space could also be a role but it is also a little more special and required field for a vaild profile where I see roles as a optional workflow UI feature.

Where the reference sits in the xml or yaml should matter much. Although quite a bit of effort is going into making the configuration files readable one of the goals of ocio, so I thought, was to not manually edit these files. I would imagine that there will be binary versions of configurations files not long after luts can be fully embedded.
 
The ascii versions should still be legible.

I was hoping to take a look at creating something which would take a ocio profile and create an embedded version. The basic idea would be to create a section at the bottom of the profile with all the luts / files that are contained in some !!binary tags. We could either update the src="foo" in the !<FileTransform> to references these embedded files or adapt the search path mechanism.

It would be nice to get some ideas on how you envisioned this stuff working, before I get carried away.

As a personal implementation preference I would only want to implement the definition of the reference as a pointer to another colorspace.
 
I think that is fine idea, what about something like.

--snip--
ocio_profile_version: 1
resource_path: luts
strictparsing: false
luma: [0.2126, 0.7152, 0.0722]
reference: lnh
roles:
  scene_linear: lnh
  compositing_log: lgh
colorspaces:
  - !<ColorSpace>
    name: lnh
...
  - !<ColorSpace>
    name: lgh
..
    to_reference: !<FileTransform> {src: lgf.spi1d, interpolation: linear}
--snip--

.malcolm



Just my 2 cents.

-Joseph



________________________________________
From: ocio...@... [ocio...@...] On Behalf Of Malcolm Humphreys [malcolmh...@...]
Sent: Monday, October 25, 2010 5:48 AM
To: OpenColorIO Developers
Subject: [ocio-dev] Reference !<Colorspace>

Do you think the 'reference' colorspace should in a separate section in the profile? This would be similar to the PCS in the icc world. It could be an extra line 'reference: !<ColorSpace> ..' before the colorspaces in the profile. The 'reference' name could be reserved so that colorspace -> reference transforms could work the same.

I can see this working as roles with ROLE_REFERENCE but it really feels like a more central OCIO concept than roles and should be separated.

Also looking at the serialization with to_referance and from_referance, I'm thinking it would be easy to read if it was structured like this? what do you think?

--from--
to_reference: !<GroupTransform>
children:
- !<FileTransform> {src: "", interpolation: unknown}
- !<CineonLogToLinTransform>
max_aim_density: [2.046, 2.046, 2.046]
neg_gamma: [0.6, 0.6, 0.6]
neg_gray_reference: [0.434995, 0.434995, 0.434995]
linear_gray_reference: [0.18, 0.18, 0.18]
from_reference: !<GroupTransform>
children:
- !<ExponentTransform> {value: [1, 1, 1, 1]}
--from--

--to--
reference:
to: !<GroupTransform>
children:
- !<FileTransform> {src: "", interpolation: unknown}
- !<CineonLogToLinTransform>
max_aim_density: [2.046, 2.046, 2.046]
neg_gamma: [0.6, 0.6, 0.6]
neg_gray_reference: [0.434995, 0.434995, 0.434995]
linear_gray_reference: [0.18, 0.18, 0.18]
from: !<GroupTransform>
children:
- !<ExponentTransform> {value: [1, 1, 1, 1]}
--to--

.malcolm



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