You protect potential for income from music by copyright registration, getting an agent, working deals with publishers, using attorneys, and other means. In today's music business the largest music publisher is iTunes, so be sure you have taken the steps to monetize via iTunes. There are others, Google Music, Spotify, etc. Digital is where the money is now and CDs and DVDs are fast becoming obsolete. My Android phone has more memory than a thousand DVDs and has all my other important stuff on it, alarm clock, camera, diary, contact list, notepad, phonebook, email, maps, files, pictures, etc. Who needs a CD player anymore when the phone has better sound and you only have one gadget to carry. Go to Amazon and search for Passman, All You Need To Know About The Music Business and read it and you will have your answer in authoritative detail.
Intellectual Property Law Attorney