There are three “non-standard” fields that I have come to rely on in my metadata:
The copyright field is just for that: copyright information (if found). The other two fields I map in my tagging software (puddle tag) to be used as:
wwwsource -> Release Page URL
wwwfileinfo -> License (Creative Commons, Artistic, Public Domain, etc.)
I did not find any plugin(s) that would make it easy to add support for handling these fields. So I’ve turned to the plugin writing documentation to see what it would take to implement these fields. Am I correct in believing the section on extending MediaFile is all I would need to follow to write a plugin that could read/write these fields? By adding these fields to the MediaFile class would they be read and stored by the importer?