Audio

Issues

Play mp3 in command line
- Packages - alsa alsa-lib
- Only root can read the audio device - Add regular user to “audio” group
- Volume control - “alsamixer”, left/right, up/down to adjust the volume
- Play mp3 in command line - ffplay from ffmpeg, play from sox with libsox-fmt-mp3
```
$ ffplay file.mp3
$ play file.mp3
```

Play sound through digital output - SPDIF

List playback devices

$ 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 0: PCH [HDA Intel PCH], device 3: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: PCH [HDA Intel PCH], device 7: HDMI 1 [HDMI 1]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

$ cat /proc/asound/devices
  1:        : sequencer
  2: [ 0- 7]: digital audio playback
  3: [ 0- 3]: digital audio playback
  4: [ 0- 2]: digital audio capture
  5: [ 0- 1]: digital audio playback
  6: [ 0- 0]: digital audio playback
  7: [ 0- 0]: digital audio capture
  8: [ 0- 3]: hardware dependent
  9: [ 0- 2]: hardware dependent
 10: [ 0]   : control
 33:        : timer

//device 0,1 is the digital output.

Unmute the S/PDIF, run “alsamixer”, switch to “S/PDIF”, press “m”.
“play” “ffplay” mp3 should work.
Play raw sound specifying the device.
```
$ aplay -D plughw:0,1 ./woman.wav
```

Reference

* http://alsa.opensrc.org/DigitalOut