[Cin] AdobeRGB and editing

Sat May 27 16:23:20 CEST 2023

сб, 27 мая 2023 г., 16:45 Andrew Randrianasulu <randrianasulu at gmail.com>:

> Slightly more from my n-th research into colorspaces.
>

https://video.stackexchange.com/questions/21483/apply-custom-lut-via-ffmpeg

this talks about using  camera-specific .cube file via ffmpeg.

=====

<https://video.stackexchange.com/posts/21653/timeline>

You may want to use FFMPEG's lut3d
<https://ffmpeg.org/ffmpeg-filters.html#lut3d-1> filter. It requires you to
provide a look-up table (a *.cube file). For example, if you have an ARRI
camera you can generate these files using ARRI Color Tool
<http://www.arri.com/camera/amira/downloads/> or simply download a package
with them from the linked page.

Once you have the files, use FFMPEG like this:

ffmpeg -i "Input.mov" -vf lut3d="ARRIP3D65PQ108-33.cube" -s 1920x1080 -c:v
dnxhd -pix_fmt yuv422p -b:v 120M DNxHD_for_Editing.mxf

=====

so, if you have those LOG videos with corresponding LUT files you can try
this in both ffmpeg command line and opts input file  ....

https://trac.ffmpeg.org/ticket/2847

this ticket says at very end lut3d uses 32-bit floating point internally,
so I guess for it to work (more or less as intended)  you need rgba-float
project type .... Also, comments warns about  "interp" parameter, default
might be different from DaVinchi

>
> https://www.slashcam.com/news/single/Adobe-After-Effects-gets-ACES-workflow-via-OpenCol-17721.html
>
> Apparently AE (After Effects) got ACES via OCIO just recently:
>
>
> ==== quote ==
> The traditional Adobe colour management engine (which uses ICC profiles)
> has to be switched to OpenColorIO in a project menu for this.
>
>
>
> Afterwards, working, composition, display and export colour spaces can be
> assigned.
>
> A plug-in effect "OCIO Color Space Transform" has also been thought of.
> This is a colour space conversion effect implemented with the OpenColorIO
> engine that can be used anywhere in the composition. This can work with CDL
> or LUT files. Complex 3D LUT interpolations are optionally performed
> tetrahedral, but this requires a supported(end) GPU.
>
> ====
>
> not sure how "working" vs "composition" differs ....
>
> Long 13 part series on color management in AE again
>
>
> https://www.provideocoalition.com/color-management-part-13-opencolorio-and-after-effects/
>
> === quote ===
>
> As I said above, using OpenColorIO is a conscious decision to do color
> management manually, instead of using the built-in color management
> system.  And this means you need to have a solid understanding of what
> you’re trying to do, and why.  OpenColorIO was created for use on large
> scale Hollywood productions, and the ACES workflows that it’s used with are
> designed to future-proof commercial content.
>
> ====
> https://www.provideocoalition.com/color-management-part-9-workflow-theory/
>
> == quote ===
>
> As explained in the video above, the point of a color managed workflow is
> that we assign our project a colorspace, and any assets which have a
> different colorspace are converted to match the project.  But if every
> component in our workflow (assets, project, monitor and output) are the
> same, then no conversion will be needed.
> ===
>
>
> c++ example looks simple, but I have no idea if it works transparently
> enough to try ...
>
>
> https://opencolorio.readthedocs.io/en/latest/guides/developing/developing.html
>
> ===
> *Convert your image, using the Processor.* Once you have a CPU or GPU
> processor, you can apply the color transformation using the “apply”
> function. In C++
> <https://opencolorio.readthedocs.io/en/latest/guides/developing/usage_examples.html#usage-applybasic-cpp>,
> you may apply the processing in-place, by first wrapping your image in an
> ImageDesc class. This approach is intended to be used in high performance
> applications, and can be used on multiple threads (per scanline, per tile,
> etc).
>
> ===
>
> so, ICC vs OCIO actually a thing ... o.o
>
> Currently in cingg you have colorspaces plugin and ffmpeg's LUT plugin,
> but no support for color-managed display or embedding icc profile in media
> ....
>
> so, *may be* you can add colorspace plugins for equating different media
> files manually, and then use external tools (olive-editor?) for
> viewing/embedding profiles ....
>
>
>
> пт, 26 мая 2023 г., 20:56 Phyllis Smith via Cin <
> cin at lists.cinelerra-gg.org>:
>
>> Updated GIT manual with Andrea's additional screen shot.  This manual
>> section as previously written by Andrea is a very helpful explanation.  It
>> is too bad that CinGG does not have better color management and most likely
>> never will. ...Phyllis
>>
>> On Fri, May 26, 2023 at 10:31 AM Andrea paz via Cin <
>> cin at lists.cinelerra-gg.org> wrote:
>>
>>> I added an image as you requested. thanks for the hint.
>>> > I guess my 'work' would benefit from RGB-Float, and only at the output
>>> > clamp to 8bit.
>>> In theory, yes. But in practice many of CinGG's internal processes
>>> (e.g., effects) do their own conversions. The result may be
>>> unpredictable. Everyone has to look for a satisfactory worflow....
>>> --
>>> Cin mailing list
>>> Cin at lists.cinelerra-gg.org
>>> https://lists.cinelerra-gg.org/mailman/listinfo/cin
>>>
>> --
>> Cin mailing list
>> Cin at lists.cinelerra-gg.org
>> https://lists.cinelerra-gg.org/mailman/listinfo/cin
>>
>
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