Change only Now Playing display without changing library

[simoncn]

I have looked at the code that implements this. The $discsubtitle value isn't supported for a top-level multidisc album, only for each album disc individually. You can use it to customise the album name that is shown by the control point when playing a track from a disc of a multidisc album.

My apologies for posting incorrect information about this. I will correct my earlier post.