I agree that this is an amazing transformation, BUT it can be very confusing. I downloaded some decades-old classical music from the Library of Congress, to use as background music for a free-of-ads YouTube, and when the video was uploaded, I got an "ownership claim" stamped on the music. Apparently this means that ads might appear on the video, with the revenue going to the owner. YouTube – I know – but still, it is so confusing!