A while ago I did a piece of work - a sort of slideshow of photos edited together like a film - that was directly inspired by a particular piece of music. The imagery wouldn't work without this track, which I didn't alter in any way. I think it's now available through Creative Commons, but I'm not sure what this means. As I've respected the music completely, i.e. not tampered with it apart from to illustrate/interpret with imagery, do I have to seek permission of the authors even though the usage is in no way commercial?