Detecting non-ICC wide-gamut PNG images in the wild

[svgeesus]

I came across this interesting quote about image color spaces from the recently released 2022 HTTP Archive report on Media:

One caveat: AVIF and PNG allow tagging images with wide-gamut color spaces using format-specific shorthands, without using ICC profiles. We started down the path of trying to detect wide-gamut AVIFs and PNGs that don’t use ICC profiles, but accounting for the various ways they are encoded—and the ways our tooling reported on them—proved a bit too complex to tackle this year. Maybe next year!

No spec link, so unclear for PNG if they are talking about gAMA and cHRM on the one hand or cICP on the other. I would expect usage for PNG to be low either way, gAMA and cHRM because it is easier and more common to drop an ICC profile into iCCP, and cICP because it is so new.

(The usage in AVIF is all CICP H.273 metadata, same as our cICP).

It would be good to work with the HTTP Archive folks to help them detect usage next year (the reports are written each year).

[svgeesus]

It would be good to work with the HTTP Archive folks to help them detect usage next year (the reports are written each year).

Closed by

• Media 2024 HTTPArchive/almanac.httparchive.org#3596 (comment)