This applet will assist with swapping, copying, and appending data between two user-chosen tags in selected tracks or tracks in the selected playlist:
Swap - swap data between tags, ex: ARTIST<->COMPOSER
Copy - copy data from one to another tag, ex: ARTIST->
Append - append data from one tag to the end of another, ex: ARTIST->COMPOSER - ARTIST
Prepend - prepend data from one tag to the beginning of another, ex: ARTIST->ARTIST - COMPOSER
The latter three actions also provide an option to delete the info from the first tag after the copy. Read Me explains all.
For OS X 10.8 or later only. This update is free for registered users of v4.x.
Select the Action to perform between the two chosen tags in each selected track.
Export selected tracks' data to XML file, import later
Locates pairs of track entries pointing to the same file
Use tag data to formulate new file name for selected tracks' files
Perform various tasks on a selection of playlists; rename, delete, duplicate, merge, more
Deletes the lyrics of every track in the Music playlist
Selected track plays after current track ends