Change only Now Playing display without changing library

[simoncn]

The Now Playing display is produced by the control point using the same metadata for albums, discs and tracks that is shown by the control point when browsing the library.

This means that changes to displayFormat settings will affect what you see in browsing as well as what you see in Now Playing.

You should be able to use displayFormat to add a single subtitle to each track without adding multiple subtitles to the album name, like this:

Title.displayFormat={$title^$discsubtitle^ (^)}