How to extract IPTC metadata from PNG files?

[drewnoakes]

Discussed in #672

^{Originally posted by dhoffer July 17, 2024}
This is what is returned.

Raw profile type iptc:
IPTC profile
36
3842494d04040000000000181c0219000c74657374312c2074657374321c020000020004

So how can I decode this to get the actual metadata tags? My understanding (limited) is that these are stored in Photoshop metadata format inside the PNG.

The actual metadata of the above as reported by exiftool.

Keywords: test1, test2

How can I decode the same with metadata-extractor?

[drewnoakes]

Sample image provided by @dhoffer:

[StefanOltmann]

Hi @drewnoakes,

It’s a hex string that just needs to be decoded back to a byte array.

I solved that in my library like this:
https://github.com/Ashampoo/kim/blob/83150150ea9e0e0aad637de72dbbf6b271cac7c2/src/commonMain/kotlin/com/ashampoo/kim/format/png/PngImageParser.kt#L166

Kind regards,

Stefan