hmm going back and memory not the most reliable but iirc if you used something like pear lyrics and one of dougs applescripts that allowed you to pay the start of each song in your library consecutively, you could effectively automate the whole of your library.
there was some tuning needed to make sure that the playing time was long enough for pear lyrics to go out to its 3 or 4 sources of lyrics, find them and then write to the mp3 or whatever music file, before the script moved onto the next song.
once you had that nailed tho, you could let it run over several days and do a large library.
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boy i'd forgotten about pear lyrics - I remember the whole david vs goliath thing that went on between the writer/designer of pear lyrics and the music companies who threatened to sue the poor guy out of existence
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oops too much wine
it's album art not lyrics obviously.
still the method is the same iirc - there were various dashboard widgets that did the same thing for album art, that pear lyrics did for lyrics. just use one of dougs applescripts in the same way.
or i could be talking out of my hat due to too much relaxant