Re: [PNG] Meeting minutes - Sep 30th, 2024

Quick follow up:
I'm currently researching the safe-to-copy bit's history, usage, etc. I
noticed that the eXIf chunk might also change to eXIF, along side mDCv &
cLLi changing to mDCV & cLLI.

The quick summary so far is all chunks are safe-to-copy unless they depend
on some data and that data might change. If a chunk depends on stored color
values, a change to those stored color values will invalidate those
dependent chunks.

This means a program like optiPNG which doesn't change stored color values
will see all existing chunks as safe-to-copy. However, optiPNG changes the
DEFLATE data. Any chunks that depend on the DEFLATE data will be
invalidated.

This scenario is proposed for a future chunk, which would mark where
DEFLATE reset markers are inserted into the DEFLATE stream. This would
allow parallel decoding.

On Mon, Sep 30, 2024 at 12:07 PM Chris Blume (ProgramMax) <
programmax@gmail.com> wrote:

> Attached is a PDF of the meeting minutes from Sep 30th, 2024.
>
> Attendance was low but that is expected so close to TPAC ending.
>
> Executive summary:
>
>    - A surprising amount of sudden work completed.
>    - mDCv & cLLi might be changing to unsafe-to-copy.
>       - Pending more clarity on the meaning of "safe-to-copy", which
>       itself is pending clarity on the definition of "PNG editor".
>    - The broadcast industry has specs blocked on PNG Third Edition
>    becoming recommended. Rally the troops!
>
> Our next meeting is Oct 14th, 2024.
> See you there!
>