Reply To: Changing the way we listen to movies??
Maybe no different from a licensing perspective, but if you are talking about songs with lyrics, there is a world of difference. Lyrics take you to the realm of the literal and do not function as underscore. However, a well-chosen piece of pre-existing instrumental music can function perfectly well as underscore, and the viewer may not have any idea that the music wasn’t written for the film in question.
If pre-existing song, classical work or whatever is similar to me. Especially for song I am not a native speaker of I can just literally switch off understanding the lyric (in Englisch) and the voice becomes just instrument. So songs do work for me if used correctly (and maybe not just song mood but text fits) exactly like any other pre-existing music used for me. Most casual viewers probably do not know (or care) if a song was originally written or not, too.