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  • The client
  • The music directory and the database
    • Mounting other storages into the music directory
    • Metadata
    • The queue
    • Stored Playlists
    • Advanced usage
      • Bit-perfect playback
      • Direct Stream Digital (DSD)
      • ICY-MetaData
      • Client Hacks
        • External Mixer
        • Troubleshooting
          • Where to start
          • Support
            • Getting Help
            • Common Problems
              • Startup
                • Error “could not get realtime scheduling”
                • Error “Failed to initialize io_uring”
                • Error “bind to ‘0.0.0.0:6600’ failed (continuing anyway, because binding to ‘[::]:6600’ succeeded)”
                • Database
                  • I can’t see my music in the MPD database
                  • MPD doesn’t read ID3 tags!
                  • Playback
                    • I can’t hear music on my client
                    • Error “Device or resource busy”
                    • Introduction

                      Music Player Daemon ( MPD ) is a flexible, powerful, server-side application for playing music. Through plugins and libraries it can play a variety of sound files while being controlled by its network protocol.

                      This document is work in progress. Most of it may be incomplete yet. Please help!

                      Installation

                      Installing on Debian/Ubuntu

                      Install the package mpd via apt :

                      apt install mpd
                      

                      When installed this way, MPD by default looks for music in /var/lib/mpd/music/; this may not be correct. Look at your /etc/mpd.conf file…

                      Debian and Ubuntu are infamous for shipping heavily outdated software. The MPD version in their respective stable releases are usually too old to be supported by this project. Ironically, the MPD version in Debian “unstable” is more stable than the version in Debian “stable”.

                      Installing on Android

                      An experimental Android build is available on Google Play. After installing and launching it, MPD will scan the music in your Music directory and you can control it as usual with a MPD client.

                      If you need to tweak the configuration, you can create a file called mpd.conf in MPD’s data directory on the external storage (usually Android/data/org.musicpd/files/mpd.conf).

                      ALSA is not available on Android; only the OpenSL ES output plugin can be used for local playback.

                      Compiling from source

                      Download the source tarball and unpack it (or clone the git repository):

                      tar xf mpd-version.tar.xz
                      cd mpd-version
                      

                      In any case, you need:

                    • a C++20 compiler (e.g. GCC 10 or clang 11)

                    • Meson 0.56.0 and Ninja

                    • pkg-config

                    • Each plugin usually needs a codec library, which you also need to install. Check the Plugin reference for details about required libraries

                      For example, the following installs a fairly complete list of build dependencies on Debian Bullseye:

                      apt install meson g++ \
                        libfmt-dev \
                        libpcre2-dev \
                        libmad0-dev libmpg123-dev libid3tag0-dev \
                        libflac-dev libvorbis-dev libopus-dev libogg-dev \
                        libadplug-dev libaudiofile-dev libsndfile1-dev libfaad-dev \
                        libfluidsynth-dev libgme-dev libmikmod-dev libmodplug-dev \
                        libmpcdec-dev libwavpack-dev libwildmidi-dev \
                        libsidplay2-dev libsidutils-dev libresid-builder-dev \
                        libavcodec-dev libavformat-dev \
                        libmp3lame-dev libtwolame-dev libshine-dev \
                        libsamplerate0-dev libsoxr-dev \
                        libbz2-dev libcdio-paranoia-dev libiso9660-dev libmms-dev \
                        libzzip-dev \
                        libcurl4-gnutls-dev libyajl-dev libexpat-dev \
                        libasound2-dev libao-dev libjack-jackd2-dev libopenal-dev \
                        libpulse-dev libshout3-dev \
                        libsndio-dev \
                        libmpdclient-dev \
                        libnfs-dev \
                        libupnp-dev \
                        libavahi-client-dev \
                        libsqlite3-dev \
                        libsystemd-dev \
                        libgtest-dev \
                        libicu-dev \
                        libchromaprint-dev \
                        libgcrypt20-dev
                      

                      Now configure the source tree:

                      meson . output/release --buildtype=debugoptimized -Db_ndebug=true
                      

                      The following command shows a list of compile-time options:

                      meson configure output/release
                      

                      NB: Check the sysconfdir setting to determine where mpd will look for mpd.conf; if you expect mpd to look for /etc/mpd.conf the sysconfdir must be ‘/etc’ (i.e., not ‘etc’ which will result in mpd looking for /usr/local/etc/mpd.conf):

                      meson configure output/release |grep sysconfdir
                      

                      If this is not /etc (or another path you wish to specify):

                      $ meson configure output/release -Dsysconfdir='/etc' ; meson configure output/release |grep syscon
                       sysconfdir              /etc                                               Sysconf data directory
                      

                      When everything is ready and configured, compile:

                      ninja -C output/release
                      

                      And install:

                      ninja -C output/release install
                      

                      Compiling for Windows

                      Even though it does not “feel” like a Windows application, MPD works well under Windows. Its build process follows the “Linux style” and may seem awkward for Windows people (who are not used to compiling their software, anyway).

                      Basically, there are two ways to compile MPD for Windows:

                    • Build as described above: with meson and ninja. To cross-compile from Linux, you need a Meson cross file.

                      The remaining difficulty is installing all the external libraries. And MPD usually needs many, making this method cumbersome for the casual user.

                    • Build on Linux for Windows using MPD’s library build script.

                    • This section is about the latter.

                      You need:

                    • mingw-w64

                    • Meson 0.56.0 and Ninja

                    • cmake

                    • pkg-config

                    • quilt

                    • Just like with the native build, unpack the MPD source tarball and change into the directory. Then, instead of meson, type:

                      mkdir -p output/win64
                      cd output/win64
                      ../../win32/build.py --64 \
                        --buildtype=debugoptimized -Db_ndebug=true \
                        -Dwrap_mode=forcefallback
                      

                      This downloads various library sources, and then configures and builds MPD (for x64; to build a 32 bit binary, pass --32). The resulting EXE files is linked statically, i.e. it contains all the libraries already and you do not need carry DLLs around. It is large, but easy to use. If you wish to have a small mpd.exe with DLLs, you need to compile manually, without the build.py script.

                      The option -Dwrap_mode=forcefallback tells Meson to download and cross-compile several libraries used by MPD instead of looking for them on your computer.

                      Compiling for Android

                      MPD can be compiled as an Android app. It can be installed easily with Google Play, but if you want to build it from source, follow this section.

                      You need:

                    • Android SDK

                    • Android NDK r25b

                    • Meson 0.56.0 and Ninja

                    • cmake

                    • pkg-config

                    • quilt

                    • Just like with the native build, unpack the MPD source tarball and change into the directory. Then, instead of meson, type:

                      mkdir -p output/android
                      cd output/android
                      ../../android/build.py SDK_PATH NDK_PATH ABI \
                        --buildtype=debugoptimized -Db_ndebug=true \
                        -Dwrap_mode=forcefallback \
                        -Dandroid_debug_keystore=$HOME/.android/debug.keystore
                      ninja android/apk/mpd-debug.apk
                      

                      SDK_PATH is the absolute path where you installed the Android SDK; NDK_PATH is the Android NDK installation path; ABI is the Android ABI to be built, e.g. “arm64-v8a”.

                      This downloads various library sources, and then configures and builds MPD.

                      Configuration

                      The Configuration File

                      MPD reads its configuration from a text file. Usually, that is /etc/mpd.conf, unless a different path is specified on the command line. If you run MPD as a user daemon (and not as a system daemon), the configuration is read from $XDG_CONFIG_HOME/mpd/mpd.conf (usually ~/.config/mpd/mpd.conf). On Android, mpd.conf will be loaded from the top-level directory of the data partition.

                      Each line in the configuration file contains a setting name and its value, e.g.:

                      connection_timeout "5"

                      For settings which specify a filesystem path, the tilde is expanded:

                      music_directory "~/Music"

                      Some of the settings are grouped in blocks with curly braces, e.g. per-plugin settings:

                      audio_output {
                          type "alsa"
                          name "My ALSA output"
                          device "iec958:CARD=Intel,DEV=0"
                          mixer_control "PCM"
                      

                      The include directive can be used to include settings from another file; the given file name is relative to the current file:

                      include "other.conf"
                      

                      You can use include_optional instead if you want the included file to be optional; the directive will be ignored if the file does not exist:

                      include_optional "may_not_exist.conf"
                      

                      Configuring the music directory

                      When you play local files, you should organize them within a directory called the “music directory”. This is configured in MPD with the music_directory setting.

                      By default, MPD follows symbolic links in the music directory. This behavior can be switched off: follow_outside_symlinks controls whether MPD follows links pointing to files outside of the music directory, and follow_inside_symlinks lets you disable symlinks to files inside the music directory.

                      Instead of using local files, you can use storage plugins to access files on a remote file server. For example, to use music from the SMB/CIFS server “myfileserver” on the share called “Music”, configure the music directory “smb://myfileserver/Music”. For a recipe, read the Satellite MPD section Satellite setup.

                      You can also use multiple storage plugins to assemble a virtual music directory consisting of multiple storages.

                      Configuring database plugins

                      If a music directory is configured, one database plugin is used. To configure this plugin, add a database block to mpd.conf:

                      database {
                          plugin "simple"
                          path "/var/lib/mpd/db"
                      

                      More information can be found in the Database plugins reference.

                      Configuring Partitions

                      MPD can have multiple “partitions”, that is, multiple independent players, each with their own queue and outputs. All partitions share one database. By default, there is only one partition called “default”. Additional partitions can be created in the configuration file with partition blocks or at runtime with the newpartition command.

                      Example for specifying an additional partition in the configuration file:

                      partition {
                          name "foo"
                      

                      The following options are available in partition blocks:

                      Configuring neighbor plugins

                      All neighbor plugins are disabled by default to avoid unwanted overhead. To enable (and configure) a plugin, add a neighbor block to mpd.conf:

                      neighbors {
                          plugin "smbclient"
                      

                      More information can be found in the Neighbor plugins reference.

                      Configuring input plugins

                      To configure an input plugin, add an input block to mpd.conf:

                      input {
                          plugin "curl"
                          proxy "proxy.local"
                      

                      The following table lists the input options valid for all plugins:

                      Configuring archive plugins

                      To configure an archive plugin, add an archive_plugin block to mpd.conf:

                      archive_plugin {
                          name "zzip"
                          enabled "no"
                      

                      The following table lists the input options valid for all plugins:

                      More information can be found in the Archive plugins reference.

                      Configuring the Input Cache

                      The input cache prefetches queued song files before they are going to be played. This has several advantages:

                    • risk of buffer underruns during playback is reduced because this decouples playback from disk (or network) I/O

                    • bulk transfers may be faster and more energy efficient than loading small chunks on-the-fly

                    • by prefetching several songs at a time, the hard disk can spin down for longer periods of time

                    • This comes at a cost:

                    • memory usage

                    • bulk transfers may reduce the performance of other applications which also want to access the disk (if the kernel’s I/O scheduler isn’t doing its job properly)

                    • To enable the input cache, add an input_cache block to the configuration file:

                      input_cache {
                          size "1 GB"
                      

                      This allocates a cache of 1 GB. If the cache grows larger than that, older files will be evicted.

                      You can flush the cache at any time by sending SIGHUP to the MPD process, see Signals.

                      Configuring decoder plugins

                      Most decoder plugins do not need any special configuration. To configure a decoder, add a decoder block to mpd.conf:

                      decoder {
                          plugin "wildmidi"
                          config_file "/etc/timidity/timidity.cfg"
                      

                      The following table lists the decoder options valid for all plugins:

                      Configuring encoder plugins

                      Encoders are used by some of the output plugins (such as shout). The encoder settings are included in the audio_output section, see Configuring audio outputs.

                      More information can be found in the Encoder plugins reference.

                      Configuring audio outputs

                      Audio outputs are devices which actually play the audio chunks produced by MPD. You can configure any number of audio output devices, but there must be at least one. If none is configured, MPD attempts to auto-detect. Usually, this works quite well with ALSA, OSS and on Mac OS X.

                      To configure an audio output manually, add one or more audio_output blocks to mpd.conf:

                      audio_output {
                          type "alsa"
                          name "my ALSA device"
                          device "hw:0"
                      

                      The following table lists the audio_output options valid for all plugins:

                      The name of the audio output. It is visible to the client. Some plugins also use it internally, e.g. as a name registered in the PULSE server.

                      format samplerate:bits:channels

                      Always open the audio output with the specified audio format, regardless of the format of the input file. This is optional for most plugins. See Global Audio Format for a detailed description of the value.

                      enabled yes|no

                      Specifies whether this audio output is enabled when MPD is started. By default, all audio outputs are enabled. This is just the default setting when there is no state file; with a state file, the previous state is restored.

                      tags yes|no

                      If set to no, then MPD will not send tags to this output. This is only useful for output plugins that can receive tags, for example the httpd output plugin.

                      always_on yes|no

                      If set to yes, then MPD attempts to keep this audio output always open. This may be useful for streaming servers, when you don’t want to disconnect all listeners even when playback is accidentally stopped.

                      always_off yes|no

                      If set to yes, then MPD never uses this audio output for playback even if it’s enabled. This can be used with the null output plugin to create placeholder outputs for other software to react to the enabled state without affecting playback.

                      mixer_type hardware|software|null|none

                      Specifies which mixer should be used for this audio output: the hardware mixer (available for ALSA alsa, OSS oss and PulseAudio pulse), the software mixer, the “null” mixer (allows setting the volume, but with no effect; this can be used as a trick to implement an external mixer, see External Mixer) or no mixer (none). By default, the hardware mixer is used for devices which support it, and none for the others.

                      replay_gain_handler software|mixer|none

                      Specifies how Replay Gain is applied. The default is software, which uses an internal software volume control. mixer uses the configured (hardware) mixer control. none disables replay gain on this audio output.

                      filters “name,…

                      The specified configured filters are instantiated in the given order. Each filter name refers to a filter block, see Configuring filters.

                      More information can be found in the Output plugins reference.

                      Configuring filters

                      Filters are plugins which modify an audio stream.

                      To configure a filter, add a filter block to mpd.conf:

                      filter {
                          plugin "volume"
                          name "software volume"
                      

                      Configured filters may then be added to the filters setting of an audio_output section, see Configuring audio outputs.

                      The following table lists the filter options valid for all plugins:

                      Configuring playlist plugins

                      Playlist plugins are used to load remote playlists (protocol commands load, listplaylist and listplaylistinfo). This is not related to MPD’s playlist directory.

                      To configure a playlist plugin, add a playlist_plugin block to mpd.conf:

                      playlist_plugin {
                          name "m3u"
                          enabled "true"
                      

                      The following table lists the playlist_plugin options valid for all plugins:

                      enabled yes|no

                      Allows you to disable a playlist plugin without recompiling. By default, all plugins are enabled.

                      as_directory yes|no

                      With this option, a playlist file of this type is parsed during database update and converted to a virtual directory, allowing MPD clients to access individual entries. By default, this is only enabled for the cue plugin.

                      More information can be found in the Playlist plugins reference.

                      Audio Format Settings

                      Global Audio Format

                      The setting audio_output_format forces MPD to use one audio format for all outputs. Doing that is usually not a good idea.

                      The value is specified as samplerate:bits:channels.

                      Any of the three attributes may be an asterisk to specify that this attribute should not be enforced, example: 48000:16:*. *:*:* is equal to not having a format specification.

                      The following values are valid for bits: 8 (signed 8 bit integer samples), 16, 24 (signed 24 bit integer samples padded to 32 bit), 32 (signed 32 bit integer samples), f (32 bit floating point, -1.0 to 1.0), dsd means DSD (Direct Stream Digital). For DSD, there are special cases such as dsd64, which allows you to omit the sample rate (e.g. dsd512:2 for stereo DSD512, i.e. 22.5792 MHz).

                      The sample rate is special for DSD: MPD counts the number of bytes, not bits. Thus, a DSD “bit” rate of 22.5792 MHz (DSD512) is 2822400 from MPD’s point of view (44100*512/8).

                      Resampler

                      Sometimes, music needs to be resampled before it can be played; for example, CDs use a sample rate of 44,100 Hz while many cheap audio chips can only handle 48,000 Hz. Resampling reduces the quality and consumes a lot of CPU. There are different options, some of them optimized for high quality and others for low CPU usage, but you can’t have both at the same time. Often, the resampler is the component that is responsible for most of MPD’s CPU usage. Since MPD comes with high quality defaults, it may appear that MPD consumes more CPU than other software.

                      Check the Resampler plugins reference for a list of resamplers and how to configure them.

                      Volume Normalization Settings

                      Replay Gain

                      The setting replaygain specifies whether MPD shall adjust the volume of songs played using ReplayGain tags. Setting this to album will adjust volume using the album’s ReplayGain tags, while setting it to track will adjust it using the “track” ReplayGain tags. auto uses the track ReplayGain tags if random play is activated otherwise the album ReplayGain tags.

                      If ReplayGain is enabled, then the setting replaygain_preamp is set to a value (in dB) between -15 and 15. This is the gain applied to songs with ReplayGain tags.

                      On songs without ReplayGain tags, the setting replaygain_missing_preamp is used instead. If this setting is not configured, then no ReplayGain is applied to such songs, and they will appear too loud.

                      ReplayGain is usually implemented with a software volume filter (which prevents Bit-perfect playback). To use a hardware mixer, set replay_gain_handler to mixer in the audio_output section (see Configuring audio outputs for details).

                      Simple Volume Normalization

                      MPD implements a very simple volume normalization method which can be enabled by setting volume_normalization to yes. It supports 16 bit PCM only.

                      Cross-Fading

                      If crossfade is set to a positive number, then adjacent songs are cross-faded by this number of seconds. This is a run-time setting which can be controlled by clients, e.g. with mpc:

                      mpc crossfade 10
                      mpc crossfade 0
                      

                      Zero means cross-fading is disabled.

                      Cross-fading is only possible if both songs have the same audio format. At the cost of quality loss and higher CPU usage, you can make sure this is always given by configuring Global Audio Format.

                      MixRamp

                      MixRamp tags describe the loudness levels at start and end of a song and can be used by MPD to find the best time to begin cross-fading. MPD enables MixRamp if:

                    • Cross-fade is enabled

                    • mixrampdelay is set to a positive value, e.g.:

                      mpc mixrampdelay 1
                      
                    • mixrampdb is set to a reasonable value, e.g.:

                      mpc mixrampdb -17
                      
                    • both songs have MixRamp tags (or mixramp_analyzer is enabled)

                    • both songs have the same audio format (or Global Audio Format is configured)

                    • The MixRamp tool can be used to add MixRamp tags to your song files. To analyze songs on-the-fly, you can enable the mixramp_analyzer option in mpd.conf:

                      mixramp_analyzer "yes"
                      

                      Listeners

                      The setting bind_to_address specifies which addresses MPD listens on for connections from clients. It can be used multiple times to bind to more than one address. Example:

                      bind_to_address "192.168.1.42"
                      bind_to_address "127.0.0.1"
                      

                      The default is “any”, which binds to all available addresses. Additionally, MPD binds to $XDG_RUNTIME_DIR/mpd/socket (if it was launched as a per-user daemon and no bind_to_address setting exists).

                      You can set a port that is different from the global port setting, e.g. “localhost:6602”. IPv6 addresses must be enclosed in square brackets if you want to configure a port:

                      bind_to_address "[::1]:6602"
                      

                      To bind to a local socket (UNIX domain socket), specify an absolute path or a path starting with a tilde (~). Some clients default to connecting to /var/run/mpd/socket so this may be a good choice:

                      bind_to_address "/var/run/mpd/socket"
                      

                      On Linux, local sockets can be bound to a name without a socket inode on the filesystem; MPD implements this by prepending @ to the address:

                      bind_to_address "@mpd"
                      

                      If no port is specified, the default port is 6600. This default can be changed with the port setting:

                      port "6601"
                      

                      These settings will be ignored if systemd socket activation is used.

                      Permissions and Passwords

                      By default, all clients are unauthenticated and have a full set of permissions. This can be restricted with the settings default_permissions and password.

                      default_permissions controls the permissions of a new client. Its value is a comma-separated list of permissions:

                      Allows reading of the database, displaying the current playlist, and current status of MPD.

                      Allows adding songs and loading playlists.

                      player

                      Allows any player and queue manipulation (start/pause/stop playback etc.).

                      control

                      Allows all other player and playlist manipulations.

                      admin

                      Allows manipulating outputs, stickers and partitions, mounting/unmounting storage and shutting down MPD.

                      local_permissions may be used to assign other permissions to clients connecting on a local socket.

                      host_permissions may be used to assign permissions to clients with a certain IP address.

                      password allows the client to send a password to gain other permissions. This option may be specified multiple times with different passwords.

                      Note that the password option is not secure: passwords are sent in clear-text over the connection, and the client cannot verify the server’s identity.

                      Example:

                      default_permissions "read"
                      host_permissions "192.168.0.100 read,add,control,admin"
                      host_permissions "2003:1234:4567::1 read,add,control,admin"
                      password "the_password@read,add,control"
                      password "the_admin_password@read,add,control,admin"
                      

                      metadata_to_use TAG1,TAG2,…

                      Use only the specified tags, and ignore the others. This setting can reduce the database size and MPD’s memory usage by omitting unused tags. By default, all tags but comment are enabled. The special value “none” disables all tags.

                      If the setting starts with + or -, then the following tags will be added or remoted to/from the current set of tags. This example just enables the “comment” tag without disabling all the other supported tags

                      metadata_to_use “+comment”

                      Section Tags contains a list of supported tags.

                      The State File

                      The state file is a file where MPD saves and restores its state (play queue, playback position etc.) to keep it persistent across restarts and reboots. It is an optional setting.

                      MPD will attempt to load the state file during startup, and will save it when shutting down the daemon. Additionally, the state file is refreshed every two minutes (after each state change).

                      state_file PATH

                      Specify the state file location. The parent directory must be writable by the MPD user (+wx).

                      state_file_interval SECONDS

                      Auto-save the state file this number of seconds after each state change. Defaults to 120 (2 minutes).

                      restore_paused yes|no

                      If set to yes, then MPD is put into pause mode instead of starting playback after startup. Default is no.

                      The Sticker Database

                      “Stickers” are pieces of information attached to songs. Some clients use them to store ratings and other volatile data. This feature requires SQLite, compile-time configure option -Dsqlite=....

                      connection_timeout SECONDS

                      If a client does not send any new data in this time period, the connection is closed. Clients waiting in “idle” mode are excluded from this. Default is 60.

                      max_connections NUMBER

                      This specifies the maximum number of clients that can be connected to MPD at the same time. Default is 100.

                      max_playlist_length NUMBER

                      The maximum number of songs that can be in the playlist. Default is 16384.

                      max_command_list_size KBYTES

                      The maximum size a command list. Default is 2048 (2 MiB).

                      max_output_buffer_size KBYTES

                      The maximum size of the output buffer to a client (maximum response size). Default is 8192 (8 MiB).

                      Zeroconf

                      If Zeroconf support (Avahi or Apple’s Bonjour) was enabled at compile time with -Dzeroconf=..., MPD can announce its presence on the network. The following settings control this feature:

                      zeroconf_name NAME

                      The service name to publish via Zeroconf. The default is “Music Player @ %h”. %h will be replaced with the hostname of the machine running MPD.

                      Satellite setup

                      MPD runs well on weak machines such as the Raspberry Pi. However, such hardware tends to not have storage big enough to hold a music collection. Mounting music from a file server can be very slow, especially when updating the database.

                      One approach for optimization is running MPD on the file server, which not only exports raw files, but also provides access to a readily scanned database. Example configuration:

                      music_directory "nfs://fileserver.local/srv/mp3"
                      #music_directory "smb://fileserver.local/mp3"
                      database {
                          plugin "proxy"
                          host "fileserver.local"
                      

                      The music_directory setting tells MPD to read files from the given NFS server. It does this by connecting to the server from userspace. This does not actually mount the file server into the kernel’s virtual file system, and thus requires no kernel cooperation and no special privileges. It does not even require a kernel with NFS support, only the nfs storage plugin (using the libnfs userspace library). The same can be done with SMB/CIFS using the smbclient storage plugin (using libsmbclient).

                      The database setting tells MPD to pass all database queries on to the MPD instance running on the file server (using the proxy plugin).

                      Real-Time Scheduling

                      On Linux, MPD attempts to configure real-time scheduling for some threads that benefit from it.

                      This is only possible if you allow MPD to do it. This privilege is controlled by RLIMIT_RTPRIO RLIMIT_RTTIME. You can configure this privilege with ulimit before launching MPD:

                      ulimit -HS -r 40; mpd
                      

                      Or you can use the prlimit program from the util-linux package:

                      prlimit --rtprio=40 --rttime=unlimited mpd
                      

                      The systemd service file shipped with MPD comes with this setting.

                      This works only if the Linux kernel was compiled with CONFIG_RT_GROUP_SCHED disabled. Use the following command(s) to check this option for your current kernel:

                      zgrep ^CONFIG_RT_GROUP_SCHED /proc/config.gz
                      grep ^CONFIG_RT_GROUP_SCHED /boot/config
                      grep ^CONFIG_RT_GROUP_SCHED /boot/config-$(uname -r)
                      

                      You can verify whether the real-time scheduler is active with the ps command:

                      # ps H -q `pidof -s mpd` -o 'pid,tid,cls,rtprio,comm'
                        PID   TID CLS RTPRIO COMMAND
                      16257 16257  TS      - mpd
                      16257 16258  TS      - io
                      16257 16259  FF     40 rtio
                      16257 16260  TS      - player
                      16257 16261  TS      - decoder
                      16257 16262  FF     40 output:ALSA
                      16257 16263 IDL      0 update
                      

                      The CLS column shows the CPU scheduler; TS is the normal scheduler; FF and RR are real-time schedulers. In this example, two threads use the real-time scheduler: the output thread and the rtio (real-time I/O) thread; these two are the important ones. The database update thread uses the idle scheduler (“IDL in ps), which only gets CPU when no other process needs it.

                      There is a rumor that real-time scheduling improves audio quality. That is not true. All it does is reduce the probability of skipping (audio buffer xruns) when the computer is under heavy load.

                      Starting and Stopping MPD

                      The simplest (but not the best) way to start MPD is to simply type:

                      This will start MPD as a daemon process (which means it detaches from your terminal and continues to run in background). To stop it, send SIGTERM to the process; if you have configured a pid_file, you can use the --kill option:

                      mpd --kill
                      

                      The best way to manage MPD processes is to use a service manager such as systemd.

                      systemd

                      MPD ships with systemd service units.

                      If you have installed MPD with your operating system’s package manager, these are probably preinstalled, so you can start and stop MPD this way (like any other service):

                      systemctl start mpd
                      systemctl stop mpd
                      

                      systemd socket activation

                      Using systemd, you can launch MPD on demand when the first client attempts to connect.

                      MPD comes with two systemd unit files: a “service” unit and a “socket” unit. These will be installed to the directory specified with -Dsystemd_system_unit_dir=..., e.g. /lib/systemd/system.

                      To enable socket activation, type:

                      systemctl enable mpd.socket
                      systemctl start mpd.socket
                      

                      In this configuration, MPD will ignore the listener settings (bind_to_address and port).

                      systemd user unit

                      You can launch MPD as a systemd user unit. These will be installed to the directory specified with -Dsystemd_user_unit_dir=..., e.g. /usr/lib/systemd/user or $HOME/.local/share/systemd/user.

                      Once the user unit is installed, you can start and stop MPD like any other service:

                      systemctl --user start mpd
                      

                      To auto-start MPD upon login, type:

                      systemctl --user enable mpd
                      
                    • SIGTERM, SIGINT: shut down MPD

                    • SIGHUP: reopen log files (send this after log rotation) and flush caches (see Configuring the Input Cache)

                    • The client

                      After you have installed, configured and started MPD, you choose a client to control the playback.

                      The most basic client is mpc, which provides a command line interface. It is useful in shell scripts. Many people bind specific mpc commands to hotkeys.

                      The MPD Wiki contains an extensive list of clients to choose from.

                      The music directory and the database

                      The “music directory” is where you store your music files. MPD stores all relevant meta information about all songs in its “database”. Whenever you add, modify or remove songs in the music directory, you have to update the database, for example with mpc:

                      mpc update
                      

                      Depending on the size of your music collection and the speed of the storage, this can take a while.

                      To exclude a file from the update, create a file called .mpdignore in its parent directory. Each line of that file may contain a list of shell wildcards. Matching files (or directories) in the current directory and all subdirectories are excluded. Example:

                      *.opus
                      

                      Subject to pattern matching is the file/directory name. It is (not yet) possible to match nested path names, e.g. something like foo/*.flac is not possible.

                      Mounting other storages into the music directory

                      MPD has various storage plugins of which multiple instances can be “mounted” into the music directory. This way, you can use local music, file servers and USB sticks at the same time. Example:

                      mpc mount foo nfs://192.168.1.4/export/mp3
                      mpc mount usbstick udisks://by-uuid-2F2B-D136
                      mpc unmount usbstick
                      

                      MPD’s neighbor plugins can be helpful with finding mountable storages:

                      mpc listneighbors
                      

                      Mounting is only possible with the simple database plugin and a cache_directory, e.g.:

                      database {
                        plugin "simple"
                        path "~/.mpd/db"
                        cache_directory "~/.mpd/cache"
                      

                      This requires migrating from the old db_file setting to a database section. The cache directory must exist, and MPD will put one file per mount there, which will be reused when the same storage is used again later.

                      Metadata

                      When scanning or playing a song, MPD parses its metadata. See Tags for a list of supported tags.

                      The metadata_to_use setting can be used to enable or disable certain tags.

                      Note that MPD may not necessarily read metadata itself, instead relying on data reported by the decoder that was used to read a file. For example, this is the case for the FFmpeg decoder: both MPD and FFmpeg need to support a given metadata format in order for metadata to be picked up correctly.

                      Only if a decoder does not have metadata support will MPD attempt to parse a song’s metadata itself.

                      The queue

                      The queue (sometimes called “current playlist”) is a list of songs to be played by MPD. To play a song, add it to the queue and start playback. Most clients offer an interface to edit the queue.

                      Stored Playlists

                      Stored playlists are some kind of secondary playlists which can be created, saved, edited and deleted by the client. They are addressed by their names. Its contents can be loaded into the queue, to be played back. The playlist_directory setting specifies where those playlists are stored.

                      Advanced usage

                      Bit-perfect playback

                      “Bit-perfect playback” is a phrase used by audiophiles to describe a setup that plays back digital music as-is, without applying any modifications such as resampling, format conversion or software volume. Naturally, this implies a lossless codec.

                      By default, MPD attempts to do bit-perfect playback, unless you tell it not to. Precondition is a sound chip that supports the audio format of your music files. If the audio format is not supported, MPD attempts to fall back to the nearest supported audio format, trying to lose as little quality as possible.

                      To verify if MPD converts the audio format, enable verbose logging, and watch for these lines:

                      decoder: audio_format=44100:24:2, seekable=true
                      output: opened plugin=alsa name="An ALSA output" audio_format=44100:16:2
                      output: converting from 44100:24:2
                      

                      This example shows that a 24 bit file is being played, but the sound chip cannot play 24 bit. It falls back to 16 bit, discarding 8 bit.

                      However, this does not yet prove bit-perfect playback; ALSA may be fooling MPD that the audio format is supported. To verify the format really being sent to the physical sound chip, try:

                      cat /proc/asound/card*/pcm*p/sub*/hw_params
                      access: RW_INTERLEAVED
                      format: S16_LE
                      subformat: STD
                      channels: 2
                      rate: 44100 (44100/1)
                      period_size: 4096
                      buffer_size: 16384
                      

                      Obey the “format” row, which indicates that the current playback format is 16 bit (signed 16 bit integer, little endian).

                      Check list for bit-perfect playback:

                    • Use the ALSA output plugin.

                    • Disable sound processing inside ALSA by configuring a “hardware” device (hw:0,0 or similar).

                    • Don’t use software volume (setting mixer_type).

                    • Don’t use Replay Gain.

                    • Don’t force MPD to use a specific audio format (settings format, audio_output_format).

                    • Verify that you are really doing bit-perfect playback using MPD’s verbose log and /proc/asound/card*/pcm*p/sub*/hw_params. Some DACs can also indicate the audio format.

                    • Direct Stream Digital (DSD)

                      DSD (Direct Stream Digital) is a digital format that stores audio as a sequence of single-bit values at a very high sampling rate. It is the sample format used on Super Audio CDs.

                      MPD understands the file formats DSDIFF and DSF. There are three ways to play back DSD:

                    • Native DSD playback. Requires ALSA 1.0.27.1 or later, a sound driver/chip that supports DSD and of course a DAC that supports DSD.

                    • DoP (DSD over PCM) playback. This wraps DSD inside fake 24 bit PCM according to the DoP standard. Requires a DAC that supports DSD. No support from ALSA and the sound chip required (except for bit-perfect 24 bit PCM support).

                    • Convert DSD to PCM on-the-fly.

                    • Native DSD playback is used automatically if available. DoP is only used if enabled explicitly using the dop option, because there is no way for MPD to find out whether the DAC supports it. DSD to PCM conversion is the fallback if DSD cannot be used directly.

                      ICY-MetaData

                      Some MP3 streams send information about the current song with a protocol named “ICY-MetaData”. MPD makes its StreamTitle value available as Title

                      By default, MPD assumes this tag is UTF-8-encoded. To tell MPD to assume a different character set, specify it in the charset URL fragment parameter, e.g.:

                      mpc add 'http://radio.example.com/stream#charset=cp1251'
                      

                      External Mixer

                      The setting mixer_type "null" asks MPD to pretend that there is a mixer, but not actually do something. This allows you to implement a MPD client which listens for mixer events, queries the current (fake) volume, and uses it to program an external mixer. For example, your client can forward this setting to your amplifier.

                      Troubleshooting

                      Where to start

                      Make sure you have the latest MPD version (via mpd --version, not mpc version). All the time, bugs are found and fixed, and your problem might be a bug that is fixed already. Do not ask for help unless you have the latest MPD version. The most common excuse is when your distribution ships an old MPD version - in that case, please ask your distribution for help, and not the MPD project.

                      Check the log file. Configure log_level "verbose" or pass --verbose to mpd.

                      Sometimes, it is helpful to run MPD in a terminal and follow what happens. This is how to do it:

                      mpd --stderr --no-daemon --verbose
                      

                      Getting Help

                      The MPD project runs a forum and an IRC channel (#mpd on Libera.Chat) for requesting help. Visit the MPD help page for details on how to get help.

                      Common Problems

                      Startup
                      Error “could not get realtime scheduling”

                      See Real-Time Scheduling. You can safely ignore this, but you won’t benefit from real-time scheduling. This only makes a difference if your computer runs programs other than MPD.

                      Error “Failed to initialize io_uring”

                      Linux specific: the io_uring subsystem could not be initialized. This is not a critical error - MPD will fall back to “classic” blocking disk I/O. You can safely ignore this error, but you won’t benefit from io_uring’s advantages.

                    • “Cannot allocate memory” usually means that your memlock limit (ulimit -l in bash or LimitMEMLOCK in systemd) is too low. 64 MB is a reasonable value for this limit.

                    • Your Linux kernel might be too old and does not support io_uring.

                    • Error “bind to ‘0.0.0.0:6600’ failed (continuing anyway, because binding to ‘[::]:6600’ succeeded)”

                      This happens on Linux when /proc/sys/net/ipv6/bindv6only is disabled. MPD first binds to IPv6, and this automatically binds to IPv4 as well; after that, MPD binds to IPv4, but that fails. You can safely ignore this, because MPD works on both IPv4 and IPv6.

                      Database
                      I can’t see my music in the MPD database
                    • Check your music_directory setting.

                    • Does the MPD user have read permission on all music files, and read+execute permission on all music directories (and all of their parent directories)?

                    • Did you update the database? (mpc update)

                    • Did you enable all relevant decoder plugins at compile time? mpd --version will tell you.

                    • MPD doesn’t read ID3 tags!
                    • You probably compiled MPD without libid3tag. mpd --version will tell you.

                    • I can’t hear music on my client
                    • That problem usually follows a misunderstanding of the nature of MPD. MPD is a remote-controlled music player, not a music distribution system. Usually, the speakers are connected to the box where MPD runs, and the MPD client only sends control commands, but the client does not actually play your music.

                      MPD has output plugins which allow hearing music on a remote host (such as httpd), but that is not MPD’s primary design goal.

                      Error “Device or resource busy”
                    • This ALSA error means that another program uses your sound hardware exclusively. You can stop that program to allow MPD to use it.

                    • Sometimes, this other program is PulseAudio, which can multiplex sound from several applications, to allow them to share your sound chip. In this case, it might be a good idea for MPD to use PulseAudio as well, instead of using ALSA directly.

                      Reporting Bugs

                      If you believe you found a bug in MPD, report it on the bug tracker.

                      Your bug report should contain:

                    • the output of mpd --version

                    • your configuration file (mpd.conf)

                    • relevant portions of the log file (--verbose)

                    • be clear about what you expect MPD to do, and what is actually happening

                    • Too Much CPU Usage

                      If you believe MPD consumes too much CPU, write a bug report with a profiling information.

                      On Linux, this can be obtained with perf (on Debian, installed the package linux-perf), for example:

                      perf record -p `pidof mpd`
                      

                      Run this command while MPD consumes much CPU, let it run for a minute or so, and stop it by pressing

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