What does it mean when music is “tracked”? Because, apparently there was a lot of it in this movie. I know chunks of TPM were used. And I know pieces of the actual soundtrack were not used.
Actually, the meaning that ‘tracking’ references is the practice of using music that is not written exclusively for the film that is being worked on. It can be music from other films, classical or contemporary music that has been released commercially (the film, ‘2001: A Space Odyssey’ is a good example), or even pop music–old and new.
There was a separate release of the AOTC soundtrack CD with one bonus track, "On The Conveyor Belt," that was sold exclusively by the store-chain, Target.
I think in the case of AOTC, it refers to the fact that Williams wrote a bunch of music that could be used for scenes which Lucas was still figuring out/editing/re-editing, especially the battle at the end. This is a very different way of doing things than the OT, wherein Williams would receive the finished (save a few minor final cuts) film and write the music to match the nearly-final cut. This allows for a lot of nice touches to the music (timing to match events on screen), but restricts the director & editor to finish his work on time and then commit to it.