HOWTO: MPD with PulseAudio independent on X

[unimatrix]

About:
This tutorial is meant for Ubuntu 9.10 Karmic Koala, but it might work in earlier or later versions as well. I wrote this tutorial mostly because it took me a full day of work using lots of help from people on #mpd and #pulseaudio from the FreeNode IRC server.

Goal:
The goal is to get the MPD daemon working using PulseAudio, but without it being dependent on the X server or a session. To do that we must configure PulseAudio to run in system-wide daemon mode (which is not recommended by the developers, but in this case we do not have a choice). This means it will be using the /etc/pulse/system.pa config file instead of the usual /etc/pulse/default.pa. We must also make sure the appropriate user/group permissions are set, or PulseAudio will be rejecting the connections.
The result will be an interrupt-less music environment, not dependent on the X server. Meaning we can for example log out and log in without the music having to stop for even a second. Switching TTYs (Ctrl+Alt+Fx) will also keep the music playing (not possible by default). All that and PulseAudio will still be able to detect and configure all your devices automatically.

Instructions:

1. 
   Make sure you add your username to the following system groups: pulse, pulse-access and audio.
   Do that by going to System --> Administration --> Users and Groups.
   Click the unlock button (the one with a picture of some keys), then click Manage Groups. In the list of groups that pops up, for each of the previously mentioned groups click "Properties" and select all the users that you want to have this functionality.
   
2. 
   Press Alt+F2 and type:
   

   gksudo gedit /etc/default/pulseaudio

   Change PULSEAUDIO_SYSTEM_START from 0 to 1 and DISALLOW_MODULE_LOADING from 1 to 0.
   
   Save the file and close the editor.
   
3. 
   (Since Ubuntu 10.04 Lucid Lynx, this step is no longer required. Instead download the attached system.pa file and place it in your /etc/pulse folder.)
   Press Alt+F2 and type:
   

   gksudo gedit /etc/pulse/system.pa

   Find this section:
   

   ### Automatically load driver modules depending on the hardware available
   .ifexists module-hal-detect.so
   load-module module-hal-detect
   .else
   ### Alternatively use the static hardware detection module (for systems that
   ### lack HAL support)
   load-module module-detect
   .endif

   Change it to:
   

   ### Automatically load driver modules depending on the hardware available
   .ifexists module-udev-detect.so
   load-module module-udev-detect
   .else
   ### Alternatively use the static hardware detection module (for systems that
   ### lack HAL support)
   load-module module-detect
   .endif

   Save the file and close the editor.
   
4. 
   Install the MPD daemon and a MPD client of your choice.
   Open Synaptic Package Manager (System --> Administration --> Synaptic Package Manager) and find the mpd package and the client of your choice (my recommendation is the GMPC client). Mark the packages for installation and click Apply.
   
5. 
   Press Alt+F2 and type:
   

   gksudo gpasswd -a mpd pulse-access

6. 
   Press Alt+F2 and type:
   

   gksudo gedit /etc/mpd.conf

   Find the following section:
   

   audio_output {
   	type		"alsa"
   	name		"My ALSA Device"
   	device		"hw:0,0"	# optional
   	format		"44100:16:2"	# optional
   	mixer_device	"default"	# optional
   	mixer_control	"PCM"		# optional
   	mixer_index	"0"		# optional
   }

   Make sure it is all commented out, by putting a # symbol in front of each line, so that it looks like this:
   

   #audio_output {
   #	type		"alsa"
   #	name		"My ALSA Device"
   #	device		"hw:0,0"	# optional
   #	format		"44100:16:2"	# optional
   #	mixer_device	"default"	# optional
   #	mixer_control	"PCM"		# optional
   #	mixer_index	"0"		# optional
   #}

   Then in the same file, add the following:
   

   audio_output {
   	type		"pulse"
   	name		"MPD PulseAudio Stream"
   }

   Save the file and close the editor.
   
7. Make sure MPD gets started after PulseAudio on boot time! Do this by properly renaming the S30mpd (it could have a different number) file in /etc/rc2.d, /etc/rc3.d, /etc/rc4.d and /etc/rc5.d to one with a number higher than that of S50pulseaudio. I suggest S60mpd.
   
8. Reboot your computer and you should be able to use MPD via PulseAudio without any interferences when switching TTYs or when killing the whole X server.

Additional Information:

• http://wiki.archlinux.org/index.php/...em-wide_daemon
• http://mpd.wikia.com/wiki/PulseAudio
• https://bugs.launchpad.net/ubuntu/+s...pd/+bug/192735

[cIIIz]

wow good stuff mate keep up the good work

[unimatrix]

wow good stuff mate keep up the good work

Thanks!

On a side note:
It would be nice if someone was willing to test everything just to confirm it works everywhere.

[tekknokrat]

Hi,

thank you for the howto.
The first steps works great to make pulseaudio running independently.

For running mpd with pulseaudio (listed in pavucontrol) it was neccessary to enable network access to local audio devices. This can be done via paprefs or with editing /etc/pulseaudio/system.pa

Put in this line in system.pa somewhere beneath ### Load several protocols:

load-module module-native-protocol-tcp

For authentication you can choose to either copy the .pulse-cookie in mpd's home dir afterwards or enable unauthorized access (in paprefs a setting beyond network access or with editing system.pa again).

copy cookie (recommended):

cp ~/.pulse-cookie /var/lib/mpd/

(Btw. the article In Arch's wiki also describes how to define a global cookie place in /etc/pulse/client.conf as an alternative.)

change to unauthorized access in system.pa (unsafe, not recommended):

load-module module-native-protocol-tcp auth-anonymous=1

Optionally, you can configure the sink in mpd.conf
Use

pactl stat

to determine the sink and put it in the config:

Default Sink: alsa_output.pci-0000_00_14.2.analog-stereo

mpd.conf:

audio_output {
        type    "pulse"
        name    "My MPD PulseAudio Output"
        server  "127.0.0.1"   # optional
#       sink    "alsa_output" # optional
        sink    "alsa_output.pci-0000_00_14.2.analog-stereo"
}

Best,
tekknokrat

[unimatrix]

Thank you for the much needed additional information and details, tekknokrat.

I just have one comment. You talk about editing default.pa. Are you sure about that? Since pulse will be running in system wide mode, shouldnt you be editing system.pa?

[tekknokrat]

Thank you for the much needed additional information and details, tekknokrat.

I just have one comment. You talk about editing default.pa. Are you sure about that? Since pulse will be running in system wide mode, shouldnt you be editing system.pa?

Hi unimatrix,
you're absolutely right. I did revert the settings from systemmode to usermode again after testing your instruction, that's why I was putting my config in default.pa all the time.

Just saw that system.pa still has the the load-module module-hal-detect. I did misread the conffile in your instructions. Will edit my comments, thank you for pointing that out!

[lancerocke]

Hi,

thank you for the howto.
The first steps works great to make pulseaudio running independently.

For running mpd with pulseaudio (listed in pavucontrol) it was neccessary to enable network access to local audio devices. This can be done via paprefs or with editing /etc/pulseaudio/system.pa

Put in this line in system.pa somewhere beneath ### Load several protocols:

load-module module-native-protocol-tcp

For authentication you can choose to either copy the .pulse-cookie in mpd's home dir afterwards or enable unauthorized access (in paprefs a setting beyond network access or with editing system.pa again).

copy cookie (recommended):

cp ~/.pulse-cookie /var/lib/mpd/

(Btw. the article In Arch's wiki also describes how to define a global cookie place in /etc/pulse/client.conf as an alternative.)

change to unauthorized access in system.pa (unsafe, not recommended):

load-module module-native-protocol-tcp auth-anonymous=1

Optionally, you can configure the sink in mpd.conf
Use

pactl stat

to determine the sink and put it in the config:


mpd.conf:

audio_output {
        type    "pulse"
        name    "My MPD PulseAudio Output"
        server  "127.0.0.1"   # optional
#       sink    "alsa_output" # optional
        sink    "alsa_output.pci-0000_00_14.2.analog-stereo"
}

Best,
tekknokrat

my '/etc/pulseaudio/system.pa' was blank

[unimatrix]

my '/etc/pulseaudio/system.pa' was blank

Was that on Lucid?

[lancerocke]

Was that on Lucid?

yes

[unimatrix]

yes

I've uploaded system.pa to the main post.