The Audio product adds an extended type of File to ZOPE. When you upload a file it extracts metadata and puts it in properties for use. This is the CMF friendly version.
In the case of MP3 files, the id3 tag metadata can be edited, and the new data will be inserted whenever the mp3 file is read out (rendered). Also, the following stuff is used for SEARCHABLE TEXT: title, description, songname, artist, album, genre, filetype.
currently no other (public) formats have this support...
THIS REQUIRES THE AUDIO PRODUCT (http://www.zope.org/Members/bowerymarc/Audio)