Incidentally, it seems very hard to make a successful film about music

just as it is very hard to write a good book about it. It's hard to find words to say what music says or does to us because it is all non-verbal, from another part of the brain. Most films and books about music fail because the authors either end up making vague but grossly exaggerating poetic claims about the value or importance of music; or they end up making a work about musicians instead, whom they do not know and imagine to be strange, other-worldly beings.