I have a DVD that I bought on Ebay that I want to back up. I made a copy of the original, and none too soon, because the original went bad on me. Now I want to make a backup from the backup copy that I made. Is there anything that prevents making a good copy from a another copy? I know this was very dicey back in VHS days because the quality degraded considerably. Does any degradation of quality happen with DVDs and DVD-Rs?