====== Pulse Audio ======
Some nice graphical tools:
<code bash>
sudo apt-get install paprefs pavucontrol
</code>
<code bash>killall pulseaudio</code>
<code>pulseudio -v</code>

<code bash>
pacmd list-sinks
pacmd list-cards
</code>



====== disable autospawn ======

<file | /etc/pulse/client.conf>
; autospawn = yes
</file>

<code bash>
pulseaudio --kill
pulseaudio -v
</code>

===== mpd player =====
  * add user ''mpd'' to ''pulse-access'' groups.
  * Configure pulse to connect to existing pulseaudio server using network

<code>
audio_output {
        type                    "pulse"
        name                    "MPD PulseAudio Output"
        server                  "127.0.0.1"
}
</code>
  * Add TCP server module to pulseaudio
<file | /etc/pulse/default.pa>
load-module module-native-protocol-tcp auth-ip-acl=127.0.0.1
</file>


===== no alsa MIC input =====

Check for existence of arecord process. It can be used to sample noise and feed a kernel entropy (package **randomsound**)

[[https://bugs.launchpad.net/ubuntu/+source/randomsound/+bug/590780]]

randomsound has to be started AFTER pulse audio. It is hard to achieve because pulse is started as from user graphical session.
As workaround it is nice to disable or remove rendomsound package.


===== Simultaneous on HDMI and Analog =====
Run paprefs, go to last tab "Simultaneous Output" and enable feature.
This will add new device for both HDMI and Analog output and set it as default one.

===== No sound =====
As as normal user try to start <code bash>pulseaudio --check</code> command:
<code>
E: [pulseaudio] core-util.c: Failed to create secure directory (/run/user/1000/pulse): Permission denied
</code>

<code bash>
ls -l /run/user/1000/
</code>
shows that pulse dir is owned by root (Probably pusleaudio was spawned when user switch to root using su or sudo)
<code>rm -r /run/user/1000/pulse</code>



===== No sound with NVidia graphic card =====
Only USB camera and NVIDIA HDMI outputs are visible.
<code bash>
pacmd list-cards

2 card(s) available.
    index: 0
	name: <alsa_card.pci-0000_01_00.1>
	driver: <module-alsa-card.c>
	owner module: 6
	properties:
		alsa.card = "1"
                alsa.card_name = "HDA NVidia"

index: 1
	name: <alsa_card.usb-046d_0825_38C54AA0-02-U0x46d0x825>
	driver: <module-alsa-card.c>
	owner module: 7
	properties:
		alsa.card = "2"
		alsa.card_name = "USB Device 0x46d:0x825"
                device.product.name = "Webcam C270"
</code>


<code bash>
$ aplay -l 
**** List of PLAYBACK Hardware Devices ****
card 0: PCH [HDA Intel PCH], device 0: ALC892 Analog [ALC892 Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: PCH [HDA Intel PCH], device 1: ALC892 Digital [ALC892 Digital]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: NVidia [HDA NVidia], device 3: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: NVidia [HDA NVidia], device 7: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: NVidia [HDA NVidia], device 8: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: NVidia [HDA NVidia], device 9: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
</code>

Reloeading UDEV detecection module doesn't help.
<code bash>
pacmd unload-module module-udev-detect && pacmd load-module module-udev-detect
</code>
After this I got doubled USB camera and NVIDIA output :(



<file /etc/pulse/default.pa>
### Load audio drivers statically
### (it's probably better to not load these drivers manually, but instead
### use module-udev-detect -- see below -- for doing this automatically)
#load-module module-alsa-sink
#load-module module-alsa-source device=hw:1,0
#load-module module-oss device="/dev/dsp" sink_name=output source_name=input
#load-module module-oss-mmap device="/dev/dsp" sink_name=output source_name=input
#load-module module-null-sink
#load-module module-pipe-sink
...
load-module module-udev-detect
...
</file>





pusleaudio -v shows lots of 
<code>
I: [pulseaudio] alsa-util.c: Error opening PCM device front:1: No such file or directory
I: [pulseaudio] (alsa-lib)pcm_hw.c: open '/dev/snd/pcmC1D0c' failed (-2)
I: [pulseaudio] alsa-util.c: Error opening PCM device hw:1: No such file or directory
</code>

<code bash>
killall pulseaudio
rm -r ~/.config/pulse/*
pulseaudio -v
</code>

load-module module-alsa-sink device=hdmi:0
load-module module-combine-sink sink_name=combined
set-default-sink combined