It hasn't been litigated yet, but the closest analog is closed captioning. You can legally create closed captions for someone elses work, and you then own the copyright.
I think the closest analog is audiobooks. You can't create audiobooks without permission from the original creator of the book. Your derivative work has it's own copyright, but it only applies to the work you've done, i.e. the audio. You can't steal someone's original work just by adding something to it. You get copyright on the addition only.