@KristijanZic I didn’t say something that seems obvious to me and has not been plainly stated.
The research into the technology and legal situation concerning ISOBMFF (.cr3, .heic, .avif and .jp2) support for Exiv2 has been completed and documented. The way ahead to achieve this in 2021 is open. It’s up to the community to make it happen and I am happy to provide support for that effort.
I’d like to thank @1div0 for his help with testing the ISOBMFF code in my book.