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MPD-configure

MPD-configure

README.md

Layout: post.
Title: README for mpd-configure.

README for mpd-configure

mpd-configure

  • The mpd-configure bash script creates a valid configuration file for mpd, optimised for bit perfect playback of any digital audio file, including those of high resolution.

  • With default settings the script uses the first available alsa audio interface by using its hardware address (in the form of hw:x,y), and has automagic procedures for things like the music directory and directory where files are stored, the number of items in the music direcory and the UPNP name. When multiple audio interfaces are found, the user is presented with a choice.

More information is available at the following pages:

Basic Usage⚓︎

Getting the Script⚓︎

Getting The Script

The latest stable version of the script may be cloned from gitlab using git:

git clone https://gitlab.com/sonida/mpd-configure.git

Using git has the added benefit that updating the script to the latest version is as easy as:

## cd /path/to/git-clone
git pull

Alternatively, the tarball of the current stable master can be downloaded and unpacked in the current directory using wget and tar:

wget https://www.musicpd.org/download/mpd/0.23/mpd-0.23.12.tar.xz | tar --strip-components=1 -zxf -

Running the Script⚓︎

Running The Script

Run the script with default settings to display the contents of the resulting mpd configuration file:

bash mpd-configure

Storing the Output of the Script in a File⚓︎

Storing Output of Script in a File

The output of the scripts can simply be redirected to a file (in this example mympd.conf):

bash mpd-configure > mympd.conf

Although the same may be achieved by using the -o or --output command line parameters or setting CONF_MPD_CONFFILE on the command line. This has the benefit that the script detects if the target file exists, in which case the user is prompted to overwrite it, while making an automated backup of the original file:

bash mpd-configure -o "mympd.conf"
# or:
CONF_MPD_CONFFILE="mympd.conf" ./mpd-configure

More Advanced Usage Example⚓︎

More Advanced Usage Example

Additional setting are available using environment variables or using the file ./mpd-configure.conf and configuration snippet files in the ./confs-available/ directory.

For example to specify CONF_MPD_MUSICDIR which sets the music_directory and saving the resulting mpd configuration file in mympd.conf, use:

CONF_MPD_MUSICDIR="/srv/media/music" ./mpd-configure -o "/etc/mpd.conf"

By default mpd-configure prompts the user to overwrite the specified file if it exists, and makes a backup of it.

Fully Automated Usage Example⚓︎

Fully Automated Usage Example

A fully automated example which does not prompt the user (-n), uses the first available USB Audio Class interface (-l u) and sets some paths, while creating a backup of the original /etc/mpd.conf in case it exists:

CONF_MPD_MUSICDIR="/srv/media/music" CONF_MPD_HOMEDIR="/var/lib/mpd" \ bash mpd-configure -l u -n -o "/etc/mpd.conf"

To see all available command line options run the script with -h or --help:

bash mpd-configure -h

Also see

About the Alsa-capabilities Helper Script⚓︎

About the Alsa-capabilities Helper Script

mpd-configure relies on the accompanying bash script alsa-capabilities for getting information about the available audio output interfaces from alsa.

About the mpd-monitor helper script⚓︎

The mpd-monitor script in this project is replaced by a separate project on gitlab.

See: mpd-monitor

Background⚓︎

Background

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. See the article. How to turn Music Player Daemon (mpd) into an audiophile music player.

It does this by creating a proper formatted audio_output configuration snippet for mpd's alsa audio output plugin using the sound cards hardware address and turning all options off which might cause mpd to alter the incoming sound. For example:

## start processing `01_output-audio-alsa.conf'
audio_output {
        type             "alsa"
        name             "Peachtree 24/192 USB X - USB Audio"
        device           "hw:1,0"
        auto_resample    "no"
        auto_format      "no"
        auto_channels    "no"
}
replaygain                 "off"
mixer_type                 "none"
## done processing

Detailed Usage Instructions⚓︎

Detailed Usage Instructions

After creating a mpd configuration file, mpd can be told to use this configuration file with:

mpd ./mpd.conf

To use the generated configuration file system wide, it can be copied to the system wide mpd configuration file when you want to run mpd as a system daemon:

sudo bash mpd-configure -o "/etc/mpd.conf"
sudo systemctl restart mpd

More Complex Usage⚓︎

More Complex Usage

For debugging or testing purposes one may set the INCLUDE_COMMENTS and/or DEBUG parameters through the mpd-configure.conf file or on the command line, eg:

DEBUG="True" INCLUDE_COMMENTS="True" bash mpd-configure

In dynamic environments in which hardware may be altered each boot, connected to whatever USB DAC, the script could be put in a logon script or systemd service file.

Usage as a Systemd Service⚓︎

Usage as a Systemd Service

The script is fast and stable enough to function as a systemd service. By setting Before=mpd.service and Wants=mpd.service in the service file systemd makes sure mpd-configure is run before mpd is started, and tries to start mpd.

Usage from within another bash or sh script⚓︎

Usage from within another bash or sh script

The bash script ./examples/bash-example.sh demonstrates the way alsa-capabilities can be used from another bash script.

This demo script returns the monitoring file of the file specified as an argument:

bash examples/bash-example.sh hw:1,0

Result:

the audio card with alsa hardware address hw:1,0 can be monitored with:
/proc/asound/card1/stream0

Usage from within Python⚓︎

Usage from within Python

Assuming your in the mpd-configure directory, run:

python examples/get-interfaces.py

The python script ./examples/get-interfaces.py uses a helper bash script (./examples/get-interfaces-for-python.sh), which in turn sources alsa-capabilities.

LTSP-specific Auto Logon Sample⚓︎

LTSP-specific Auto Logon Sample

For my LTPS-environments the script directory can be copied to the home directory of the auto logon user specified in /var/lib/tftpboot/ltsp/i386/lts.conf. It's ~/.profile should be edited to run the script and start mpd using the script generated ~/.mpd/mpd.conf, ie:

systemctl stop mpd && \
CONF_MPD_MUSICDIR="/srv/media/music" CONF_MPD_HOMEDIR="/var/lib/mpd" \
bash ~/mpd-configure/mpd-configure -l usb -n -q --nobackup -o "~/.mpd/mpd.conf"  && \
systemctl start mpd

Preferences⚓︎

Preferences

Preferences can be set in the file mpd-configure.conf. By default all preferences are commented out.

The script uses configuration file snippets in the ./confs-available/ directory. By symlinking them to the ./confs-enabled/ directory, they will be included by mpd-configure in the resulting mpd configuration file. Any bash variable in those configuration snippets, will be expanded to their calculated values by the script.

General Environment Variables⚓︎

General Environment Variables

DEBUG Output values of variables and program flow to std_err for easier debugging. Possible values:

  • commented out: disabled (Default).
  • 1 (or non-empty): enabled.

INCLUDE_COMMENTS Include commented and empty lines from configuration snippet files in the generated mpd configuration file:

  • commentend out: disabled (Default).
  • 1 (or non-empty): enabled

CONF_MPD_CONFFILE Path to where the generated mpd configuration file will be written. Possible values:

  • commented out: don't write to a file (Default). One may redirect the output of the script using:
bash mpd-configure > /path/to/mpd.conf
  • /path/to/mpd.conf: use the path specified.

Alsa and Sound⚓︎

Alsa and Sound

LIMIT_INTERFACE_TYPE A keyword which limits the type of alsa interfaces to be returned:

Possible values:

  • usb, digital or analog
  • Comment it out (or leave it empty) to prevent filtering.

Default value:

  • commented out (or empty ""): do not limit the interfaces that will be found.

LIMIT_INTERFACE_FILTER The available output devices (after filtering with LIMIT_INTERFACE_TYPE when applicable) may be further limited using a regular expression (which thus is case sensentive) which should match the output of:

LANG=C aplay -l | grep ^card

If for example the output is like this:

card 0: MID [HDA Intel MID], device 0: HDMI 0 [HDMI 0]
card 1: receiv [Pink Faun USB 32/384 USB receiv], device 0: USB Audio [USB Audio]

... you could use one of the following values to match the second line (which in this example matches the alsa hw:1,1 interface, eg. the second interface of the second sound card):

"USB Audio"
"[uU][sS][bB] \w+ "

but not

"USB audio"

Possible values:

  • empty or commented out: no filtering is applied
  • Some regular expression: use the (first) interface which matches the regexp.

Default value:

  • commented out (or empty ""): use the first available interface.

Handling of pulseaudio OPT_DISABLE_PULSEAUDIO Disable pulseaudio by modifyin the current users' ~/.pulseaudio/client.conf

Possible values:

  • non-empty (1 or "True") disables pulseaudio.
  • Comment it out (or leave it empty) to prevent disabling of pulseaudio.

Default value:

  • commented out (or empty ""): do not disable it.

OPT_STOP_PULSEAUDIO Temporary disable and stop pulseaudio during detection of alsa interfaces. After the script pulseaudio's client configuration and run state will restored.

Possible values:

  • non-empty (1 or "True") temporary disables and stops pulseaudio.
  • Comment it out (or leave it empty) to prevent temporary disabling and stopping of pulseaudio.

Default value:

  • commented out (or empty ""): do not disable it.

See the configuration snippet files and accompanying README in ./confs-available for additional parameters and and explanation for their functions.

Reference for both MPD/LTSP.⚓︎

Reference for both MPD/LTSP.

MPD specific:

LTSP specific: