Difference between revisions of "Music Player Daemon"

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(Re-write and unification of recent)
(Local Configuration (per user))
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Line 53: Line 53:
 
  mkdir -p ~/.mpd/playlists
 
  mkdir -p ~/.mpd/playlists
 
  cp /usr/share/doc/mpd/mpdconf.example ~/.mpd/mpd.conf
 
  cp /usr/share/doc/mpd/mpdconf.example ~/.mpd/mpd.conf
  touch ~/.mpd/{database,log,state}
+
  touch ~/.mpd/{database,log,state,pid}
  
 
Edit {{ic|~/.mpd/mpd.conf}} and specify the requisite files:
 
Edit {{ic|~/.mpd/mpd.conf}} and specify the requisite files:
Line 88: Line 88:
 
X-GNOME-Autostart-enabled=false</pre>
 
X-GNOME-Autostart-enabled=false</pre>
  
==== Start MPD per user with systemd ====
+
==== Autostart with systemd ====
 +
 
 +
{{Note|1=As of 2013-03-20 this functionality is still in development ([https://bbs.archlinux.org/viewtopic.php?pid=1208585 forum thread]).  However, there is a workaround though it is peculiar as it requires a running X.org server to work.}}
 +
 
 +
'''Expected setup'''
 +
 
 +
* Start user-session service (e.g. {{ic|sudo systemctl enable user-session@USERNAME}}).
 +
* Add local service file {{ic|~/.config/systemd/user/mpd.service}} (see below).
 +
* Start local systemd {{ic|systemd --user &}}; enable service file {{ic|systemctl --user enable mpd}}; start it {{ic|systemctl --user start  mpd}}.
 +
* Add {{ic|systemd --user &}} to {{ic|~/.profile}} or another autostart file.
 +
* Reboot and MPD start.
 +
 
 +
<pre>[Unit]
 +
Description=Music Player Daemon
 +
 
 +
[Service]
 +
ExecStart=/usr/bin/mpd %h/.config/mpd/mpd.conf --no-daemon
 +
ExecStop= /usr/bin/mpd %h/.config/mpd/mpd.conf --kill
 +
 
 +
[Install]
 +
WantedBy=default.target</pre>
 +
 
 +
'''Current setup''' (this hasn't worked for everybody)
  
 
As recommended above, it is best to use MPD as a service per user. In this case, we will use {{ic|~/.mpd/mpd.conf}} and not start mpd.service as a daemon for the whole system and all users.
 
As recommended above, it is best to use MPD as a service per user. In this case, we will use {{ic|~/.mpd/mpd.conf}} and not start mpd.service as a daemon for the whole system and all users.
Line 132: Line 154:
  
 
==== Scripted Configuration ====
 
==== Scripted Configuration ====
Rasi has written a script that will create the proper directory structure, configuration files and prompt for the location of the user's Music directory; it can be downloaded [http://53280.de/dl/mpdsetup.tar here].
+
Rasi has written a script that will create the proper directory structure, configuration files and prompt for the location of the user's Music directory; it can be downloaded [http://53280.de/dl/mpdsetup.sh here].
  
 
=== Global Configuration ===
 
=== Global Configuration ===
{{Note|For user-specific permissions, change the "user" line above to reflect one of the system users.}}
 
 
{{Warning|Users of PulseAudio with a local 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!}}
 
{{Warning|Users of PulseAudio with a local 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!}}
  
MPD comes with an example configuration file, available at {{ic|/usr/share/doc/mpd/mpdconf.example}}. This file holds an abundance of information on MPD configuration, and holds default mixer values.
+
The default Arch install keeps the setup in {{ic|/var/lib/mpd}} and uses ''mpd'' as default user.
 
+
Normally,{{ic|/etc/mpd.conf}} is created when installing mpd. If not, copy the included example file to {{ic|/etc/mpd.conf}}.
+
# cp /usr/share/doc/mpd/mpdconf.example /etc/mpd.conf
+
 
+
==== Editing mpd.conf ====
+
The default Arch install keeps the setup in {{ic|/var/lib/mpd}} and uses "mpd" as default user.
+
  
 
Edit {{ic|/etc/mpd.conf}} to reflect as such:
 
Edit {{ic|/etc/mpd.conf}} to reflect as such:
 
{{hc|/etc/mpd.conf|
 
{{hc|/etc/mpd.conf|
music_directory      "/home/user/music"
+
music_directory      "/path/to/music/dir"
 
playlist_directory    "/var/lib/mpd/playlists"
 
playlist_directory    "/var/lib/mpd/playlists"
 
db_file              "/var/lib/mpd/mpd.db"
 
db_file              "/var/lib/mpd/mpd.db"
log_file              "/var/log/mpd/mpd.log"
+
log_file              "syslog"
 
pid_file              "/run/mpd/mpd.pid"
 
pid_file              "/run/mpd/mpd.pid"
 
state_file            "/var/lib/mpd/mpdstate"
 
state_file            "/var/lib/mpd/mpdstate"
 
user                  "mpd"
 
user                  "mpd"
# bind_to_address      "127.0.0.1"
 
# port                  "6600"
 
 
}}
 
}}
Now change permissions for mpd to write to {{ic|/var/log/mpd/mpd.log}}, otherwise mpd will return an error when it is started. The best way is to make the {{ic|/var/log/mpd/mpd.log}} belong to the mpd [[Users and Groups#Group management|user]].
 
  # chown -R mpd /var/log/mpd 
 
Run this to create the /run/mpd dir:
 
  # systemd-tmpfiles --create mpd.conf
 
To change the volume for mpd independent from other programs, uncomment or add this switch in mpd.conf:
 
  
 +
We just configured MPD to run as the ''mpd'' user, but {{ic|/var/lib/mpd}} is owned by ''root'' by default, we need to change this so ''mpd'' can write here:
 +
# chown -R mpd /var/lib/mpd
 +
 +
==== Music directory ====
 +
MPD needs to have {{ic|+x}} permissions on ''all'' parent directories to the music collection (ie. if it's located outside of {{ic|/var/lib/mpd}}). Thus users will most likely need to remount the music directory under a directory that mpd has access to -- this only applies if running as the 'mpd' user.
 +
 +
# mkdir /var/lib/mpd/music
 +
# echo "/path/to/music/dir /var/lib/mpd/music none bind" >> /etc/fstab
 +
# mount -a
 +
Also see [https://bbs.archlinux.org/viewtopic.php?id=86449 this forum thread].
 +
 +
An additional solution would be to just create a symbolic link into {{ic|/var/lib/mpd/music}}.
 +
# mkdir /var/lib/mpd/music
 +
# ln -s /path/to/music/dir /var/lib/mpd/music/
 +
 +
If the music collection is contained under multiple directories, create symbolic links under the main music directory in {{ic|/var/lib/mpd}}. Remember to set permissions accordingly on the directories being linked.
 +
 +
==== Start MPD ====
 +
MPD can be controlled with the ''mpd'' [[daemon]]. The first startup can take some time as MPD will scan your music directory.
 +
 +
Test everything by starting a client application ({{Pkg|ncmpc}} is a light and easy to use client), and play some music!
 +
 +
==== Configure audio ====
 +
{{Note|Everything should work by default, only change this if it doesn't work for you!}}
 +
To change the volume for mpd independent from other programs, uncomment or add this switch in mpd.conf:
 
{{hc|/etc/mpd.conf|
 
{{hc|/etc/mpd.conf|
 
mixer_type "software"
 
mixer_type "software"
 
}}
 
}}
  
Users of [[PulseAudio]] will need to make the following modification:
+
Users of [[ALSA]] will want to have the following device definition, which allows software volume control in the MPD client to control the volume separately from other applications.
 
{{hc|/etc/mpd.conf|2=
 
{{hc|/etc/mpd.conf|2=
 
audio_output {
 
audio_output {
         type                   "pulse"
+
         type           "alsa"
         name                   "pulse audio"
+
         name           "My Sound Card"
 +
        mixer_type      "software"      # optional
 
}
 
}
 
}}
 
}}
  
Users of [[ALSA]] will want to have the following device definition, which allows software volume control in the MPD client to control the volume separately from other applications.
+
Users of [[PulseAudio]] will need to make the following modification:
 
{{hc|/etc/mpd.conf|2=
 
{{hc|/etc/mpd.conf|2=
 
audio_output {
 
audio_output {
         type            "alsa"
+
         type            "pulse"
         name            "My Sound Card"
+
         name            "pulse audio"
        mixer_type      "software"      # optional
+
 
}
 
}
 
}}
 
}}
  
 +
==== Changing user ====
 +
{{Note|This is only required if you change the 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" "player_thread: problems opening audio device while playing "Song Name.mp3""
 
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" "player_thread: problems opening audio device while playing "Song Name.mp3""
  
 
This is because by default MPD runs as member of '''audio''' group and the sound devices under {{Ic|/dev/snd/}} are owned by this group, so add user {{Ic|mpd}} to group {{Ic|audio}}.
 
This is because by default MPD runs as member of '''audio''' group and the sound devices under {{Ic|/dev/snd/}} are owned by this group, so add user {{Ic|mpd}} to group {{Ic|audio}}.
 
  # gpasswd -a mpd audio
 
  # gpasswd -a mpd audio
 
===== Music directory =====
 
MPD needs to have {{ic|+x}} permissions on ''all'' parent directories to the music collection (ie. if it's located outside of "mpd" home directory {{ic|/var/lib/mpd}}). By default useradd sets permissions on home directories to {{ic|1700 drwx------}}. Thus users will most likely need to remount the music directory under a directory that mpd has access to -- this only applies if running as the 'mpd' user.
 
 
# mkdir /var/lib/mpd/music
 
# echo "/home/$USER/music /var/lib/mpd/music none bind" >> /etc/fstab
 
# mount -a
 
# systemctl restart mpd.service
 
Also see [https://bbs.archlinux.org/viewtopic.php?id=86449 this forum thread.]
 
 
An additional solution would be to just create a symbolic link into {{ic|/var/lib/mpd/music}}.
 
# mkdir /var/lib/mpd/music
 
# ln -s MUSIC_FOLDER /var/lib/mpd/music/
 
# systemctl restart mpd.service
 
 
If the music collection is contained under multiple directories, create symbolic links under the main music directory in {{ic|/var/lib/mpd}}. Remember to set permissions accordingly on the directories being linked.
 
 
==== Creating the required files ====
 
Now, having finished configuring MPD, the files and directories for MPD to write in need to be created:
 
 
Create the directories and files specified in {{ic|/etc/mpd.conf}}:
 
# mkdir -p /var/lib/mpd/playlists
 
# touch /var/lib/mpd/{mpd.db,mpdstate}
 
 
Usually the init-script should properly create {{ic|/run/mpd/}} when starting. The daemon will use this directory to create {{ic|mpd.pid}} in it. However, when running mpd as a different user, requires an update to the tmpfiles.d: copy {{ic|/usr/lib/tmpfiles.d/mpd.conf}} to {{ic|/etc/tmpfiles.d/mpd.conf}}:
 
Change:
 
d /run/mpd 0755 mpd mpd
 
to:
 
d /run/mpd 0755 ''username'' ''groupname''
 
 
Change the file's permissions so that the daemon can modify them.
 
# chown -R mpd /var/lib/mpd
 
 
==== Create database ====
 
Creating the database is now accomplished via the update feature of the client, for example {{ic|mpc update}}. You'll need to install the mpc package for this. It is in the official repositories
 
{{Box RED | Note: | Creating the MPD database as root using {{ic|# mpd --create-db}} is deprecated.}}
 
  
 
==== Timeline of MPD startup ====
 
==== Timeline of MPD startup ====

Revision as of 17:11, 14 May 2013

Template:Article summary start Template:Article summary text Template:Article summary heading Template:Article summary wiki Template:Article summary wiki Template:Article summary heading Template:Article summary text Template:Article summary end

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

Stable version

The latest stable version of mpd is available in the official repositories.

Git version

Should users wish to run an experimental version, the AUR offers several from which to choose. For example, mpd-gitAUR.

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.

For a proper MPD operation these are the necessary files and directories:

  • mpd.db - The music database
  • mpd.pid - The file where mpd stores its process ID
  • mpd.log - mpd logs here
  • mpdstate - mpd's current state is noted here
  • playlists - the folder where playlists are saved into

In order for MPD to be able to play back audio, ALSA, PulseAudio or OSS needs to be setup and working.

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

To setup: create a directory for the required files and the playlists; copy the example configuration locally; create all of the requisite files:

mkdir -p ~/.mpd/playlists
cp /usr/share/doc/mpd/mpdconf.example ~/.mpd/mpd.conf
touch ~/.mpd/{database,log,state,pid}

Edit ~/.mpd/mpd.conf and specify the requisite files:

~/.mpd/mpd.conf
music_directory    "~/music"          # Can keep commented if XDG music dir.
playlist_directory "~/.mpd/playlists"
db_file            "~/.mpd/database"
log_file           "~/.mpd/log"
pid_file           "~/.mpd/pid"
state_file         "~/.mpd/state"

MPD can now be started by typing mpd on the command line (mpd first searches for ~/.mpd.conf, then ~/.mpd/mpd.conf, and then for /etc/mpd.conf [there is no support for XDG-config directory ~/.config/mpd/mpd.conf]). To specify the location of the configuration file :

mpd ~/.config/mpd/mpd.conf

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

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

To start with the X.org server add to either xprofile or xinitrc. Some DEs ignore these files (GNOME does) and a desktop file must be placed in ~/.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

Autostart with systemd

Note: As of 2013-03-20 this functionality is still in development (forum thread). However, there is a workaround though it is peculiar as it requires a running X.org server to work.

Expected setup

  • Start user-session service (e.g. sudo systemctl enable user-session@USERNAME).
  • Add local service file ~/.config/systemd/user/mpd.service (see below).
  • Start local systemd systemd --user &; enable service file systemctl --user enable mpd; start it systemctl --user start mpd.
  • Add systemd --user & to ~/.profile or another autostart file.
  • Reboot and MPD start.
[Unit]
Description=Music Player Daemon

[Service]
ExecStart=/usr/bin/mpd %h/.config/mpd/mpd.conf --no-daemon
ExecStop= /usr/bin/mpd %h/.config/mpd/mpd.conf --kill

[Install]
WantedBy=default.target

Current setup (this hasn't worked for everybody)

As recommended above, it is best to use MPD as a service per user. In this case, we will use ~/.mpd/mpd.conf and not start mpd.service as a daemon for the whole system and all users. We will NOT use the /usr/lib/systemd/system/mpd.service which is intended to start the mpd.service as root and for all users.

Note: It is recommended to follow the instructions in the Systemd/User page fully, and to have your whole session managed by systemd --user.

If you already enabled it, just disable it first:

 # systemctl disable mpd.service

If you used to start mpd inside your ~/.xinitrc, comment or delete the line

mpd ~/.mpdconf

Then, edit a new file ~/.config/systemd/user/mpd.service

~/.config/systemd/user/mpd.service
[Unit]
Description = Music Player Daemon

[Service]
ExecStart = /usr/bin/mpd --no-daemon
Restart = always

[Install]
WantedBy = default.target

Then, add this line to .xinitrc before any exec <session-command>

~/.xinitrc
#run systemd as user instance
systemd --user &

Log out, log in your xsession. Let's first check mpd is not running. If yes, just kill it. If not, continue to the next step.

$ ps -ef | grep mpd

Now, enable and start mpd.service as per user

$ systemctl --user enable mpd
$ systemctl --user start mpd

Check the mpd status and see if mpd.service is correctly enabled and started

$ systemctl --user status mpd

Scripted Configuration

Rasi has written a script that will create the proper directory structure, configuration files and prompt for the location of the user's Music directory; it can be downloaded here.

Global Configuration

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

The default Arch install keeps the setup in /var/lib/mpd and uses mpd as default user.

Edit /etc/mpd.conf to reflect as such:

/etc/mpd.conf
music_directory       "/path/to/music/dir"
playlist_directory    "/var/lib/mpd/playlists"
db_file               "/var/lib/mpd/mpd.db"
log_file              "syslog"
pid_file              "/run/mpd/mpd.pid"
state_file            "/var/lib/mpd/mpdstate"
user                  "mpd"

We just configured MPD to run as the mpd user, but /var/lib/mpd is owned by root by default, we need to change this so mpd can write here:

# chown -R mpd /var/lib/mpd

Music directory

MPD needs to have +x permissions on all parent directories to the music collection (ie. if it's located outside of /var/lib/mpd). Thus users will most likely need to remount the music directory under a directory that mpd has access to -- this only applies if running as the 'mpd' user.

# mkdir /var/lib/mpd/music
# echo "/path/to/music/dir /var/lib/mpd/music none bind" >> /etc/fstab
# mount -a

Also see this forum thread.

An additional solution would be to just create a symbolic link into /var/lib/mpd/music.

# mkdir /var/lib/mpd/music
# ln -s /path/to/music/dir /var/lib/mpd/music/

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 the mpd daemon. 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!

Configure audio

Note: Everything should work by default, only change this if it doesn't work for you!

To change the volume for mpd independent from other programs, uncomment or add this switch in mpd.conf:

/etc/mpd.conf
mixer_type			"software"

Users of ALSA will want to have the following device definition, which allows software volume control in the MPD client to control the volume separately from other applications.

/etc/mpd.conf
audio_output {
        type            "alsa"
        name            "My Sound Card"
        mixer_type      "software"      # optional
}

Users of PulseAudio will need to make the following modification:

/etc/mpd.conf
audio_output {
        type            "pulse"
        name            "pulse audio"
}

Changing user

Note: This is only required if you change the 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" "player_thread: problems opening audio device while playing "Song Name.mp3""

This is because by default MPD runs as member of audio group and the sound devices under /dev/snd/ are owned by this group, so add user mpd to group audio.

# 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.

Multi-mpd setup

Useful if 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).

Clients

A separate client is needed to control mpd. Popular options are:

Console

  • mpc — Simple KISS client. All basic functionality available
http://mpd.wikia.com/wiki/Client:Mpc || mpc
  • ncmpc — A NCurses client for mpd
http://mpd.wikia.com/wiki/Client:Ncmpc || ncmpc
  • ncmpcpp — An almost exact clone of ncmpc with some new features written in C++ (tag editor, search engine)
http://unkart.ovh.org/ncmpcpp/ || ncmpcpp
  • pms — Highly configurable and accessible ncurses client
http://pms.sourceforge.net/ || pmusAUR
  • vimpc — ncurses based MPD client with vi-like key bindings
http://sourceforge.net/projects/vimpc/ || vimpcAUR

Graphical

  • Ario — A very feature-rich GTK2 GUI client for mpd, inspired by Rhythmbox
http://ario-player.sourceforge.net/ || ario
  • QmpdClient — A GUI client written with Qt 4.x
http://bitcheese.net/wiki/QMPDClient || qmpdclient
  • Sonata — An elegant Python GTK+ client
http://sonata.berlios.de/ || sonata
  • gmpc — GNOME Client
http://gmpc.wikia.com/wiki/Gnome_Music_Player_Client || gmpc
  • Dmpc — Dmenu-based MPC client with a playlist manager and state-saving on playlist changes
http://wintervenom.mine.nu/ || dmpcAUR
  • Cantata — High-feature, Qt4/KDE4 client for MPD with very configurable interface
https://code.google.com/p/cantata/ || cantata-qtAUR

Web

  • Patchfork — web client for MPD written in PHP and Ajax
http://mpd.wikia.com/wiki/Client:Pitchfork || patchfork-gitAUR.

See a long list of clients at the mpd wiki.

External links