AOMediaCodec / libavif

libavif - Library for encoding and decoding .avif files
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Support copy png description metadata to avif description #1564

Open Kieaer opened 1 year ago

Kieaer commented 1 year ago

Same title. When converting png format to avif, png description metadata is lost.

y-guyon commented 1 year ago

Thank you for the report.

Is there a PNG file example that you can share?

Do you know if another format than AVIF keeps the description when converted from PNG?

kmilos commented 1 year ago

AFAIK, there is no specific "AVIF description" metadata in the AVIF container specification?

The equivalent of PNG "Description" would be I guess either the ImageDescription Exif tag, or the dc:description XMP one.

IMHO, it's probably less overkill to create the XMP payload w/ a single tag, than the Exif one (as there are quite a few mandatory tags to be filled in then).

While at it, it could be useful to map other PNG text properties to equivalent XMP dc schema ones if applicable.

But all of this might be out of scope for libavif...

I'd instead encourage you to use XMP or Exif directly (instead of specific PNG properties), as those are readily supported and transferred between PNG and AVIF (and many more formats).

Kieaer commented 1 year ago

@y-guyon I've never heard of copying descriptions between different formats. Here's example png contains description in metadata https://drive.google.com/file/d/11x84VJFjMdYI8M0Eb0lMqvj1e7YNiqcA/view?usp=sharing

Kieaer commented 1 year ago

@kmilos After downloading the Image from the Google Drive link above, you can check the PNG:Description at the site below. https://exifmeta.com/

I already tried using Exiftool, but the only thing that didn't copy was the png description.

maryla-uc commented 1 year ago

I agree with @kmilos that the best way would probably be to convert the metadata to XMP. However, I have a few concerns:

All in all, I think we can keep the issue open to see if there is more interest, but I would consider this low priority.