Agree with all the above - it HAS to be detailed in the contract. While there are different practices (low budget productions vs. big companies etc.) but the important guideline to follow is - various licensing rights taken from the author, should be well reflected in the sum he gets. And please, do not confuse those, with performance royalties, which are paid by broadcast entities, and no matter what, the original composer is stated in the PRO registry (companies are usually written in as publishers of the music, so they get their split too).
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