Metadata: Extract Notes from UserComment field

[chuckweger]

Describe what problem this solves and why this would be valuable to many users
The popular utility exiftool can be used to add tags to photos which are then imported into PhotoPrism. However, exiftool cannot insert the "Comments" tag into iOS-created HEIC photos, because "Comments" is apparently a legacy JPEG-only tag, and does not exist in EXIF or IPTC namespaces.

Describe the solution you'd like
exiftool can, however, insert the EXIF "UserComment" tag into HEIC photos, but PhotoPrism ignores this tag.

A solution would be to map the UserComment tag into PhotoPrism's Notes field, just as PhotoPrism maps the Comments tag now. If both tags happened to be in a file, then it's your choice which one to map (probably Comments to conform to legacy behavior).

Describe alternatives you've considered
The only alternative I can think of is to pre-convert any HEIC file into JPEG format before importing. This is both time-consuming and risks losing other metadata in the file.

Additional context
To test, pick any HEIC photo and try this command:

exiftool -Comment="A fabulous image" [somefilename].HEIC

This command fails in exiftool because it does not support adding that tag to HEIC files.

Instead, do this:

exiftool -UserComment="A fabulous image" [somefilename].HEIC

This correctly inserts the tag into the HEIC file, but currently PhotoPrism does not ingest that tag.

A sample HEIC image containing the UserComment tag is attached. It's in a zip file because GitHub also apparently doesn't support HEIC files.

IMG_0402.HEIC.zip