Music Player Daemon: Difference between revisions
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* {{App|[http://lacocina.nl/audiophile-mpd mpd-configure]|Create a MPD configuration optimized for [https://www.musicpd.org/doc/user/advanced_usage.html#bit_perfect bit perfect] audio playback, without any resampling or conversion, using the ALSA interface hardware address (hw:x,y)|https://github.com/ronalde/mpd-configure|no package}} | * {{App|[http://lacocina.nl/audiophile-mpd mpd-configure]|Create a MPD configuration optimized for [https://www.musicpd.org/doc/user/advanced_usage.html#bit_perfect bit perfect] audio playback, without any resampling or conversion, using the ALSA interface hardware address (hw:x,y)|https://github.com/ronalde/mpd-configure|no package}} | ||
=== | === System-wide configuration === | ||
{{Note|Users of PulseAudio with a global MPD have to implement a [[Music Player Daemon/Tips and tricks#Local (with separate mpd user)|workaround]] in order to run MPD as its own user!}} | {{Note|Users of PulseAudio with a global MPD have to implement a [[Music Player Daemon/Tips and tricks#Local (with separate mpd user)|workaround]] in order to run MPD as its own user!}} |
Revision as of 09:28, 6 May 2018
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-gitAUR for the development version.
Configuration
MPD is able to run in the #Local configuration (per user) mode, in the #Global configuration mode (settings apply to all users), and in multiple instances #Multi-mpd setup mode. 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, optionally with PulseAudio, needs to be setup and working.
MPD is configured in the file mpd.conf(5) which can be located in various locations depending on the setup chosen (see below). These are the commonly used configuration options:
pid_file
- The file where MPD stores its process IDdb_file
- The music databasestate_file
- MPD's current state is noted hereplaylist_directory
- The folder where playlists are saved intomusic_directory
- The folder that MPD scans for musicsticker_file
- The sticker database
Local configuration (per user)
MPD can be configured per user. Running it as a normal user has the benefits of:
- Using a single directory
~/.config/mpd/
(or any other directory under$HOME
) that contains all the MPD configuration files. - It is easier to avoid unforeseen directory and file permission errors.
Configure the location of files and directories
In user mode, the configuration is read from $XDG_CONFIG_HOME/mpd/mpd.conf
.
We will assume here $XDG_CONFIG_HOME
equals ~/.config
which is the recommended XDG base directory specification.
To build the user configuration, the example configuration file included in the package is a good starting point, copy it using the following lines:
$ mkdir ~/.config/mpd $ cp /usr/share/doc/mpd/mpdconf.example ~/.config/mpd/mpd.conf
A good practice is to use this newly created ~/.config/mpd/
directory to store, together with the configuration file, other MPD related files like the database or the playlists. The user must have read write access to this directory.
Then edit the configuration file in order to specify the required and optional files and directories:
~/.config/mpd/mpd.conf
# Required files db_file "~/.config/mpd/database" log_file "syslog" # The music directory is by default the XDG directory, uncomment to amend and choose a different directory #music_directory "~/Music" # Uncomment to refresh the database whenever files in the music_directory are changed #auto_update "yes" # Uncomment to enable the functionalities #playlist_directory "~/.config/mpd/playlists" #pid_file "~/.config/mpd/pid" #state_file "~/.config/mpd/state" #sticker_file "~/.config/mpd/sticker.sql"
If playlists are enabled in the configuration, the specified playlist directory must be created:
$ mkdir ~/.config/mpd/playlists
MPD can now be started (an optional custom location for the configuration file can be specified):
$ mpd [config_file]
To build the database scanning into the music_directory
defined above, a MPD client must be used, for example with mpc the command is:
$ mpc update
or alternatively one can set the option auto_update
to "yes"
in the configuration to refresh the database whenever files are changed in music_directory
.
Audio configuration
If ALSA is used, autodetection of the default ALSA device should work out of the box without any particular setting. If not, the syntax for ALSA audio output definition is provided thereafter; the required name
parameter specifies a unique name for the audio output.
~/.config/mpd/mpd.conf
audio_output { type "alsa" name "ALSA sound card" }
Users of PulseAudio will need to make the following modification:
~/.config/mpd/mpd.conf
audio_output { type "pulse" name "pulse audio" }
User will also have to edit /etc/pulse/client.conf
and change the autospawn
option to yes
in order to allow the MPD user to use pulseaudio. It will be necessary to restart pulseaudio after making this modification.
Autostart with systemd
The mpd package provides a user service file. 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.
start/enable the user unit mpd.service
(i.e. with the --user
flag).
~/.config/mpd/mpd.conf
, see systemd#Editing provided units if you would like to indicate a custom configuration file path.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
Scripted configuration
The following tool provides assistance for MPD configuration:
- mpd-configure — Create a MPD configuration optimized for bit perfect audio playback, without any resampling or conversion, using the ALSA interface hardware address (hw:x,y)
- https://github.com/ronalde/mpd-configure || no package
System-wide configuration
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 the configuration file /etc/mpd.conf
.
MPD needs to have execute permission on all parent directories of 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:
- Use instead the #Local configuration (per user) mode
- Add the MPD user to the user's group and grant group execute permission to the user directory. This way the MPD user has permission to open the user directory:
# gpasswd -a mpd user_group $ chmod 710 /home/user_directory
- Store the music collection in a different path (a) by moving it entirely, (b) with a bind mount or (c) with Btrfs#Subvolumes (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 configuration file must define 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 with systemd
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
mpd provides a mpd.socket
unit. If mpd.socket
is enabled (and mpd.service
is disabled), systemd will not start MPD immediately, it will just listen to the appropriate sockets. Then, whenever an MPD client attempts to connect to one of these sockets, systemd will start mpd.service
and transparently hand over control of these ports to the MPD process.
If you prefer to listen to different UNIX sockets or network ports (even multiple sockets of each type), or if you prefer not to listen to 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).
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:
- Since MPD is started as root by systemd, it first reads the
/etc/mpd.conf
file. - MPD reads the user variable in the
/etc/mpd.conf
file, and changes from root to this user. - 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.
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
- ncmpc — Ncurses client for MPD
- ncmpcpp — Almost exact clone of ncmpc with some new features written in C++ (tag editor, search engine)
- pms — Highly configurable and accessible ncurses client written in Go
- vimpc — Ncurses based MPD client with vi-like key bindings
- vimus — MPD client with vim-like key bindings, written in Haskell
- https://github.com/vimus/vimus || no package
Graphical
- Ario — Very feature-rich GTK2 GUI client for MPD, inspired by Rhythmbox
- QMPDClient — Qt4 GUI client
- Sonata — Elegant Python GTK+ client
- 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.
- Cantata — High-feature, Qt4, Qt5 or KDE client for MPD with very configurable interface
- Xfmpc — A graphical GTK+ MPD client focusing on low footprint
- pymp'd — A GTK+ front end client for the music playing daemon MPD
- Quimup — A simple Qt5 frontend for MPD written in C++
- SkyMPC — A simple MPD client, powered by Qt5
See also
- MPD Forum
- MPD User Manual
- Wikipedia article
- mopidy is an alternative to MPD written in Python. Note it is not a complete MPD replacement, its advantage is that it has plug-ins for playing music from cloud services like Spotify, SoundCloud, and Google Play Music. However, the project is not that active and some of its plugins are not maintained.