PMP is a client-server music system. The server, which plays music and manages and keeps track of music files, runs in the background and is controlled by one or more clients. The client serves only as a remote control for the server. There is a graphical client available, and also a limited command-line client.
PMP has advanced file tracking. This means that music files are identified by a hash value instead of the location of the file in the file system. PMP can deal with files that were moved or renamed behind its back; it will still recognize the file and therefore playback history will not be lost. PMP will also detect copies of a file as being the same, so playback history will be shared for all copies. Tags in the file (like ID3 for MP3 files) don't take part in the identification of the file, so when a file is copied and its tags changed in the copy, PMP will still see that it's the same track as the original file.
PMP is a multi-user system. Users are required to authenticate themselves when connecting to the server. PMP keeps a separate play history for each user. A score for each track is calculated from the user's play history, so each user has their own personal scores.
PMP uses a queue for playback, not a playlist. Tracks are added to the queue and played in FIFO (first in first out) order. The queue can of course be modified by the user during playback; insertion/removal/moving of tracks in the queue is possible. Playlists will be supported in the future, but they will be used simply as a source to populate the queue. Breakpoints can be inserted into the queue; these will cause playback to stop when reached.
PMP is free and open source software.
PMP on GitHub
You can contact the developer here: firstname.lastname@example.org