[Cin] Two links on ICC in MP4

[Andrew Randrianasulu]

пт, 11 апр. 2025 г., 20:05 Andrew Randrianasulu <randrianasulu at gmail.com>:

> Starter thread, at least back in time (2022) it was not easy/possible to
> use ffmpeg for adding custom icc profile to mp4 container but MP4Box from
> gpac project was up to task:
>
>
> https://superuser.com/questions/1739082/embedding-a-custom-icc-profile-in-an-mp4-with-ffmpeg
>
> =====
>
> Creating MP4 video without ICC profile (for testing):
> ffmpeg -y -loop 1 -framerate 1 -i icc_chelsea.png -vcodec libx265 -t 10
> chelsea.mp4
>
> Extracting the ICC profile:
> magick icc_chelsea.png profile.icc
>
> Adding the ICC profile to the MP4 video file using MP4Box:
> MP4Box -add video.mp4#video:colr=prof,profile.icc -new icc_video.mp4
>
> Testing with FFprobe:
> ffprobe icc_chelsea.mp4
>
> ===== end of quotation ====
> As far as I understand in this case idea was to embed display profile into
> media. But few apps outside of Final Cut Pro/quicktime can do anything
> useful about this info?
>
> https://forum.luminous-landscape.com/index.php?topic=129232.0
>
> this one from ~2019.
>
> It states that instead of more flexible color management video world used
> few fixed mode monitor color spaces, and whole process was a bit manual if
> your input image/video was not in one of those.
>
> I think we hit crudest form of this limitation when we try to fade
> titler's text over png image. It sort of flashes, due to missing
> (unapplied) 2.4 gamma step?
>

https://www.cinelerra-gg.org/bugtracker/view.php?id=559#c5098

probably should be simple enough to replicate in custom BlendAlgebra format
..... ?

As it was indicated not all PNGs are in sRGB so it makes sense for ffmpeg
to not embed this step into decoder itself?
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