What this workflow means
A YouTube URL is an input method, not a rights shortcut
The original song supplies melody, lyrics, timing, phrasing, and much of the expression. Voice conversion changes the lead vocal identity toward your trained model. You still need permission for the cloned voice and any rights required for the composition, recording, upload, adaptation, and publication. Public availability on YouTube does not mean unrestricted reuse.
Understand song generation vs voice conversion
