Music Player Daemon

Related articles

• MPD/Tips and Tricks
• MPD/Troubleshooting

MPD (music player daemon) is an audio player that has a server-client architecture. It plays audio files, organizes playlists and maintains a music database all while using very few resources. In order to interface with it, a separate client is needed.

Installation

Install the mpd package, or mpd-git^AUR for the development version.

Note: An alternative implementation written in Python called Mopidy exists. It is available as mopidy and mopidy-git^AUR. Be warned that is not a complete MPD drop-in replacement. The advantage of Mopidy over MPD is that it has plug-ins for playing music from cloud services like Spotify, SoundCloud, and Google Play Music. However, mopidy project is not as active and many plugins become unusable or buggy at least over time.

Setup

MPD is able to run locally (per user settings), globally (settings apply to all users), and in multiple instances. The way of setting up mpd depends on the way it is intended to be used: a local configuration may prove more useful on a desktop system, for example.

In order for MPD to be able to playback audio, ALSA or OSS (optionally with PulseAudio) needs to be setup and working.

MPD is configured in mpd.conf. The location of this file depends on how you want to run MPD (see the sections below). These are commonly used configuration options:

• pid_file - The file where mpd stores its process ID
• db_file - The music database
• state_file - MPD's current state is noted here
• playlist_directory - The folder where playlists are saved into
• music_directory - The folder that MPD scans for music
• sticker_file - The sticker database

Global configuration

Warning: Users of PulseAudio with a global mpd have to implement a workaround in order to run mpd as its own user!

The default /etc/mpd.conf keeps the setup in /var/lib/mpd which is assigned to user as well as primary group mpd.

Music directory

The music directory has to be set by parameter music_directory in file /etc/mpd.conf:

music_directory "/path/to/music"

MPD needs to have +x permissions on all parent directories to the music collection and also read access to all directories containing music files. This conflicts with the default configuration of the user directory where many users store their music.

While there are several solutions to this problem one of these should be most practical:

• run MPD as user
• add the mpd user to your login group and grant group permission to your user directory:

 # gpasswd -a mpd <your login group>
 $ chmod 710 /home/<your home dir>

• put your music collection to a different path (a) by moving it entirely, (b) with a bind mount or (c) with a Btrfs subvolume (you should make this change persistent with an entry to /etc/fstab ). Permissions of alternate directories can be adjusted with Access Control Lists.

The MPD config must contain only one music directory. If the music collection is contained under multiple directories, create symbolic links under the main music directory in /var/lib/mpd. Remember to set permissions accordingly on the directories being linked.

Start MPD

MPD can be controlled with mpd.service using systemd. The first startup can take some time as MPD will scan your music directory.

Test everything by starting a client application (ncmpc is a light and easy to use client), and play some music!

Socket activation

If the mpd.socket unit (provided by mpd) is enabled while mpd.service is disabled, systemd will not start mpd immediately, but it will listen on the appropriate sockets. When an mpd client attempts to connect on one of those sockets, systemd will start mpd.service and transparently hand over control of those ports to the mpd process.

If you prefer to listen on different UNIX sockets or network ports (even multiple sockets of each type), or if you prefer not to listen on network ports at all, edit the mpd.socket unit appropriately and modify /etc/mpd.conf to match the configuration (see mpd.conf(5) for details).

Configure audio

Users of ALSA will want to have the following device definition; replace My Sound Card with the name of a sound card or pcm (aplay --list-pcms).

/etc/mpd.conf

audio_output {
        type            "alsa"
        name            "My Sound Card"
        mixer_type      "software"      # optional
}

The mixer_type "software" option tells 'mpd' to use its own independent software volume control.

Users of PulseAudio will need to make the following modification:

/etc/mpd.conf

audio_output {
        type            "pulse"
        name            "pulse audio"
}

User will also have to edit /etc/pulse/client.conf and change the default autospawn = no line to autospawn = yes in order to allow the mpd user to use pulseaudio. It will be necessary to restart pulseaudio after making this modification.

Changing user

Changing the group that MPD runs as may result in errors like output: Failed to open "My ALSA Device", [alsa]: Failed to open ALSA device "default": No such file or directory or player_thread: problems opening audio device while playing "Song Name.mp3".

This is because the MPD users need to be part of the audio group to access sound devices under /dev/snd/. To fix it add user make the MPD user part of the audio group:

# gpasswd -a mpd audio

Timeline of MPD startup

To depict when MPD drops its superuser privileges and assumes those of the user set in the configuration, the timeline of a normal MPD startup is listed here:

1. Since MPD is started as root by systemd, it first reads the /etc/mpd.conf file.
2. MPD reads the user variable in the /etc/mpd.conf file, and changes from root to this user.
3. MPD then reads the contents of the /etc/mpd.conf file and configures itself accordingly.

Notice that MPD changes the running user from root to the one named in the /etc/mpd.conf file. This way, uses of ~ in the configuration file point correctly to the home user's directory, and not root's directory. It may be worthwhile to change all uses of ~ to /home/username to avoid any confusion over this aspect of MPD's behavior.

Local configuration (per user)

MPD can be configured per user (rather than the typical method of configuring MPD globally). Running MPD as a normal user has the benefits of:

• A single directory ~/.config/mpd/ (or any other directory under $HOME) that will contain all the MPD configuration files.
• Easier to avoid unforeseen read/write permission errors.

Good practice is to create a single directory for the required files and playlists. It can be any directory for which you have read and write access, e.g. ~/.config/mpd/ or ~/.mpd/. This section assumes it is ~/.config/mpd/, which corresponds to the default value of $XDG_CONFIG_HOME (part of XDG Base Directory Specification).

MPD searches for a config file in $XDG_CONFIG_HOME/mpd/mpd.conf and then ~/.mpdconf. It is also possible to pass other path as command line argument.

Copy the example configuration file to desired location, for example:

$ mkdir -p ~/.config/mpd
$ cp /usr/share/doc/mpd/mpdconf.example ~/.config/mpd/mpd.conf

Edit ~/.config/mpd/mpd.conf and specify the required files:

~/.config/mpd/mpd.conf

# Required files
db_file            "~/.config/mpd/database"
log_file           "~/.config/mpd/log"

# Optional
music_directory    "~/Music"
playlist_directory "~/.config/mpd/playlists"
pid_file           "~/.config/mpd/pid"
state_file         "~/.config/mpd/state"
sticker_file       "~/.config/mpd/sticker.sql"

Create the playlist directory as configured above:

$ mkdir ~/.config/mpd/playlists

When the paths of required files are configured, MPD can be started. To specify custom location of the configuration file:

$ mpd config_file

Autostart on tty login

To start MPD on login add the following to ~/.profile (or another autostart file):

# MPD daemon start (if no other user instance exists)
[ ! -s ~/.config/mpd/pid ] && mpd

Autostart in X

If you use a desktop environment, place the following file in ~/.config/autostart/:

~/.config/autostart/mpd.desktop

[Desktop Entry]
Encoding=UTF-8
Type=Application
Name=Music Player Daemon
Comment=Server for playing audio files
Exec=mpd
StartupNotify=false
Terminal=false
Hidden=false
X-GNOME-Autostart-enabled=false

If you do not use a DE, place the line from #Autostart on tty login in your autostart file.

Autostart with systemd

The mpd package provides a user service file. The configuration file is expected to exist either in ~/.mpdconf or ~/.config/mpd/mpd.conf; see systemd#Editing provided units if you would like to use a different path. The service starts the process as user, there is no need to change permission nor use the user and group variables in the MPD configuration file.

All you have to do is start/enable the user unit mpd.service (i.e. with the --user flag).

Note: mpd also provides a system service file. The process is started as root and reads the #Global configuration from /etc/mpd.conf rather than the #Local configuration (per user).

Scripted configuration

You can use a script to create the proper directory structure, configuration files and prompt for the location of the user's Music directory.

Scripted configuration for bit perfect playback

You can use a bash script to also create a valid mpd configuration file which focusses on bit perfect audio playback. That is playback without any resampling or format conversion. It does this by setting audio output parameters to use a direct alsa hwardware address (like `hw:0,0`). The script detects and lists which playback interfaces alsa supports. When one interface is found it uses that one, if multiple are found it prompts the user which one to use. When not specified on the command line, it auto configures things like the music_directory and mpd's home directory by using freedesktop.org XDG configuration.

Multi-mpd setup

Running an icecast server

For a second MPD (e.g., with icecast output to share music over the network) using the same music and playlist as the one above, simply copy the above configuration file and make a new file (e.g., /home/username/.mpd/config-icecast), and only change the log_file, error_file, pid_file, and state_file parameters (e.g., mpd-icecast.log, mpd-icecast.error, and so on); using the same directory paths for the music and playlist directories would ensure that this second mpd would use the same music collection as the first one e.g., creating and editing a playlist under the first daemon would affect the second daemon as well. Users do not have to create the same playlists all over again for the second daemon. Call this second daemon the same way from ~/.xinitrc above. (Just be sure to have a different port number, so as to not conflict with the first mpd daemon).

Satellite setup

The method above works, but at least in theory could lead to issues with the database, when both mpd instances try to write to the same database file. MPD has a satellite mode where one instance can receive the database from an already running mpd instance.

in your config-icecast add this, where host and port reflect your primary mpd server.

database {
    plugin "proxy"
    host "localhost"
    port "6600"
}

Clients

A separate client is needed to control mpd. See a long list of clients at the mpd website. Popular options are:

Console

• mpc — Command line user interface for MPD server

http://www.musicpd.org/clients/mpc/ || mpc

• ncmpc — Ncurses client for mpd

http://www.musicpd.org/clients/ncmpc/ || ncmpc

• ncmpcpp — Almost exact clone of ncmpc with some new features written in C++ (tag editor, search engine)

http://ncmpcpp.rybczak.net/ || ncmpcpp

• pms — Highly configurable and accessible ncurses client

https://ambientsound.github.io/pms/ || pmus-git^AUR

• vimpc — Ncurses based MPD client with vi-like key bindings

https://github.com/boysetsfrog/vimpc || vimpc-git^AUR

• vimus — MPD client with vim-like key bindings, written in Haskell

https://github.com/vimus/vimus || vimus-git^{AUR[broken link: package not found]}

Graphical

• Ario — Very feature-rich GTK2 GUI client for mpd, inspired by Rhythmbox

http://ario-player.sourceforge.net/ || ario

• QmpdClient — GUI client written with Qt 4.x

http://bitcheese.net/wiki/QMPDClient || qmpdclient

• Sonata — Elegant Python GTK+ client

http://www.nongnu.org/sonata/ || sonata

• gmpc — GTK2 frontend for Music Player Daemon. It is designed to be lightweight and easy to use, while providing full access to all of MPD's features. Users are presented with several different methods to browse through their music. It can be extended by plugins, of which many are available.

http://gmpclient.org/ || gmpc

• Cantata — High-feature, Qt4, Qt5 or KDE client for MPD with very configurable interface

https://github.com/CDrummond/cantata || cantata

• Xfmpc — A graphical GTK+ MPD client focusing on low footprint

http://goodies.xfce.org/projects/applications/xfmpc || xfmpc

• pymp'd — A GTK+ front end client for the music playing daemon MPD

http://pympd.sourceforge.net || pympd

• Quimup — A client for the music player daemon (MPD) written in C++ and QT3 / since v. 1.4.0 the code was migrated to Qt5 for MPD 0.17.0 and above

http://goodies.xfce.org/projects/applications/xfmpc || quimup^AUR

• SkyMPC — A simple MPD client, powered by Qt5

https://github.com/soramimi/SkyMPC || skympc-git^AUR

See also

• MPD Forum
• MPD User Manual
• Wikipedia article