I don't want to use the iOS app for creating playlists as the functionality is transient. I want to be able to create and store playlists on my NAS and access them through the iOS app.
Is this possible and can anybody suggest suitable software I could install on the NAS to accomplish this?
Thanks in anticipation.
You do not need any particular software. Simply put a .m3u file in a folder (for instance, one named "playlists") which is scanned by your UPnP server. In the .m3u file, put the URLs of the files you want to play in the desired sequence. For example, I have made a "test" folder with a "list.m3u" file containing the two lines:
file:///mnt/hdd4/share/audio/data/Yevgeny Sudbin/Scriabin (2006)/01-10-No_3_Nuances-SMR.flac
file:///mnt/hdd4/share/audio/data/Yevgeny Sudbin/Scriabin (2006)/01-13-Waltz_in_A_flat_major_Op_38-SMR.flac
Navigating to "test" in the folder view made available by MinimServer to my control point (I use Linn Kazoo) and selecting "list" shows the content of "list.m3u". You can then select to the whole playlist, single tracks, etc. as for a standard album.
I use by the way the same approach for streaming internet radio stations. I have setup MinimServer to scan two directories: share/audio/data and share/audio/streams. I have all my music files in the first directory and playlists (mainly URLs of internet radio stations) in the second.
MinimServer allows you to browse all your resources seamlessly, no matter whether these are actual music files, playlists, symbolic links, etc. Any decent UPnP server should allow you to do the same.