A contractor is in charge of hiring musicians for a recording session for film and television. In England and other parts of the world, contractors are known as "fixers."
Contractors, with the assistance of the composer and others, will choose and hire musicians according to the requirements of the production, arrange for recording studio availability, and make sure the musicians are paid. During recording sessions, the contractor will track the amount of music recorded, make sure that musicians are given appropriate breaks, and generally oversee the musicians as they perform as part of the recording process.
Contractors also handle musicians' union paperwork on recording jobs that are done under union contracts, and are a very helpful source of information about how to work successfully with the musicians' union.