What is scratch music/temp track?
Internet Filmmakers' FAQ
Scratch music or a temp track is simply music that is used in a film during the editing process to help create mood and atmosphere, but will not be used in the final release. Often editors use scratch music to help their audience (ie. director, producer, financiers, etc) get a feel for the movie before the actual score is completed. Scratch music may also be used to demonstrate to a composer the type of music wanted for a scene (particularly in cases where the production can't afford the rights for the scratch music used!)