PNG and APNG Incorrect Colors Because of Tags

[Jay123210599]

I heard that if you add colorimetry flags to videos without them, or for videos with colorimetry flags already present, if you make PNG files out of it, the ffmpeg PNGs will display incorrect colors in many programs, including browsers because of gAMA and cHRM tag issues. Is that true, and if so, why? How do I fix it?

[MasterQuestionable]

͏    Havoc unfixable:
͏    ​https://github.com/libjxl/libjxl/issues/4056#issuecomment-2607405171

͏    ExifTool may be used to strip the various tags.
͏    Nevertheless, it's recommended to use WebP Lossless instead of PNG. (superior compression)

[Jay123210599]

Replying to MasterQuestionable:

͏    Havoc unfixable:
͏    ​https://github.com/libjxl/libjxl/issues/4056#issuecomment-2607405171

͏    ExifTool may be used to strip the various tags.
͏    Nevertheless, it's recommended to use WebP Lossless instead of PNG. (superior compression)

What do you mean? It can't be fixed? Why?

[MasterQuestionable]

͏    Trace the links for the technical background. (the unfixable presentation havoc)
͏    But to somewhat mitigate:
͏    Probably fixing #11002 (by not generating alike PNG meta) could help.

[Jay123210599]

Replying to MasterQuestionable:

͏    Trace the links for the technical background. (the unfixable presentation havoc)
͏    But to somewhat mitigate:
͏    Probably fixing #11002 (by not generating alike PNG meta) could help.

Wait, what's havoc, and why does it cause PNG and APNG to show incorrect colors because of tag issues? Why isn't it fixable?

[MasterQuestionable]

͏    Some ill designs in the past standards unjustifiably sophisticated the presentation, and made which tricky unfixable.

͏    ----

͏    ​https://trac.ffmpeg.org/ticket/11002#comment:11
͏    `exiftool "-Gamma=200" "0.png" -o "1.png"`

[Leo Izen]

Replying to Jay123210599:

I heard that if you add colorimetry flags to videos without them, or for videos with colorimetry flags already present, if you make PNG files out of it, the ffmpeg PNGs will display incorrect colors in many programs, including browsers because of gAMA and cHRM tag issues. Is that true, and if so, why? How do I fix it?

This is not true, so there's no need to fix it. If you have an actual PNG that you believe is displaying incorrectly in a browser that is generated by FFmpeg then you should open a separate issue. Preferably you should only open issues if you have observed the bug, rather than "have heard" about it.