This is not true. Given two songs A, B, an informed human can tell whether A and B are the same song or not. Now you’ve created a UNIQUE constraint on your data, so you have a unique identifier.
To the extent that "an informed human" and "the same song" have meaningful definitions of "informed" and "same", you've just recreated the problem.
They live in situ with the file, and multiple encodings of the same canonical "song" may not be identical.