metaflac let me add whatever tags I want:
% metaflac --set-tag="XXX=YYY" test.flac % metaflac --show-tag="XXX" test.flac XXX=YYY
I'd like to add metadata for personal use (where I bought it, what I paid, personal rating, etc.), but I don't want to simply say
COST=$1.23, as the keyword "COST" might someday be added as a standard tag.
Is there an existing standard or convention for creating tag-names for user-defined metadata within the standard namespace?