Re: [PNG] Meeting topics

   - ISO 21496-1 <https://www.iso.org/standard/86775.html> (gain maps)
      - Any update on ISO possibly making this freely available?

See this thread here:
https://lists.w3.org/Archives/Public/public-png/2025Sep/0007.html

Based on that, I suggest we assume we are not going to get the spec public
and work off the shared internal spec with the W3C PNG group for the same
of making sure we get ISO 21496-1 incorporated in PNG.

I am happy to discuss this proposal in the meeting.

Sincerely,
Fares

On Fri, Sep 26, 2025 at 12:12 PM Chris Blume (ProgramMax) <
programmax@gmail.com> wrote:

> Hello everyone,
> We have a meeting this coming Monday. Here are some topics we can discuss.
> Feel free to reply with any topics you would like to add/alter.
>
>    - Discussion topics
>       - C2PA
>       <https://spec.c2pa.org/specifications/specifications/2.2/specs/C2PA_Specification.html#_embedding_manifests_into_png> (provenance
>       and authenticity)
>          - Last time, we asked how widely used it is. It sounds like
>          billions of PNGs have been produced with the 'caBX' chunk, since AI systems
>          include it when producing images.
>          - Given this many images with 'caBX', perhaps we don't need to
>          rename the chunk to 'cABX' when adding it to the spec.
>       - SMPTE ST 2094-10 <https://github.com/w3c/png/issues/311> (tone
>       mapping metadata)
>          - We're waiting for more information. As such, this might be
>          more of a status update report here than a discussion topic.
>       - SMPTE 2094-50 <https://github.com/SMPTE/st2094-50> (gain curves)
>          - A draft was just made public 3 days ago (follow link above).
>          - Should we add a chunk for this?
>          - T.35 <https://www.itu.int/rec/T-REC-T.35-200002-I> is related.
>       - ISO 21496-1 <https://www.iso.org/standard/86775.html> (gain maps)
>          - Any update on ISO possibly making this freely available?
>          - Last meeting, we learned that W3C strongly prefers referencing
>          freely available specs but makes exceptions. And that ISO is unlikely to
>          make specs free (although, I recall we managed this in the past?).
>          - If it seems unlikely for the spec to become freely available,
>          should we continue with some new chunks?
>       - Updates
>       - Apple will help with the iDOT extension.
>       - FileReadSpeedTest
>       <https://github.com/ProgramMax/FileReadSpeedTest> tool created to
>       help identify & test decoding performance goals.
>
>