Troubleshooting operating system audio

If audio isn't working for OpenVoiceOS, it's useful to verify that the operating system audio is working.

Architecture

ALSA

ALSA is the kernel level sound mixer, it manages your sound card directly. ALSA is crap (seriously) and it can handle a few (sometimes just one) channel. We don't generally have to deal with ALSA directly.

ALSA can be configured to use PulseAudio as it's default device, that way ALSA applications that are not PulseAudio aware will still use PulseAudio via an indirection layer.

Pulse Audio

PulseAudio is a software mixer, running in user space. When it runs, it uses Alsa's channel and manages everything. mixing, devices, network devices, etc.

PulseAudio always uses ALSA as backend, and on startup opens all ALSA devices. Since most ALSA devices can't be opened multiple times, this will cause all ALSA applications that try to use an ALSA device directly when PulseAudio is running to fail. If you have a legacy application that for some reason doesn't work, you can use pasuspender to temporary suspend PulseAudio to run this particular application.

Pulse Audio Modules

Troubleshooting Commands

List hardware cards cat /proc/asound/cards List Playback and capture devices visible to ALSA (note the Card Number)

aplay -l
arecord -l

This will list the cards, which can then be referenced in arecord using -D hw:,0:

arecord -f dat -r 16000 -D hw:4,0 -c 4 -d 10 test2.wav

You can then play the file back to test your speakers

aplay -D hw:2,0 test2.wav

** If PulseAudio is installed, Alsa should be configured to use PulseAudio as it's default, and we don't change anything in Alsa, we configure our default sources and sinks in Pulse Audio**

Verify that pulseaudio is installed

apt list pulseaudio

Verify that Alsa is using Pulse Audio as the default

$ aplay -L | head -n9
null
    Discard all samples (playback) or generate zero samples (capture)
default
    Playback/recording through the PulseAudio sound server

PulseAudio

List sinks (speakers) and sources (microphones) visible to PulseAudio

pactl list sinks
pactl list sources

This will list the sources that can be used to set the default source for pulseaudio below.

pacmd set-default-source

e.g.

pacmd set-default-source alsa_input.usb-OmniVision_Technologies__Inc._USB_Camera-B4.09.24.1-01.multichannel-input

Gather Data

Before submitting an issue or asking a question on Element, please gather the following data.

For Microphone issues:

arecord -l
arecord -L | head -n9
pactl list sources
pacmd dump

For Speaker issues:

aplay -l
aplay -L | head -n9
pactl list sinks
pacmd dump

Additional Resources

• PulseAudio Troubleshooting

Problem/fix

ERROR: pulseaudio sink always suspended

Try disabling suspend-on-idle in /etc/pulse/default.pa

Change this:

### Automatically suspend sinks/sources that become idle for too long
load-module module-suspend-on-idle

to this:

### Automatically suspend sinks/sources that become idle for too long
#load-module module-suspend-on-idle

and restart pulseaudio

pulseaudio -k
pulseaudio --start

ERROR: All media play requests loop (silently) until ovos restart

When running OVOS headless and trying to play media and seeing this in the logs over and over:

Nov 05 19:00:15 mycroft ovos-audio.sh[1614]: 2023-11-05 19:00:15.457 - audio - ovos_utils.file_utils:resolve_resource_file:153 - WARNING - Deprecation version=0.1.0. Caller=ovos_utils.gui:812. Expected a dict config and got None.
Nov 05 19:00:15 mycroft ovos-audio.sh[1614]: 2023-11-05 19:00:15.465 - audio - ovos_utils.file_utils:resolve_resource_file:153 - WARNING - Deprecation version=0.1.0. Caller=ovos_utils.gui:813. Expected a dict config and got None.
Nov 05 19:00:15 mycroft ovos-audio.sh[1614]: 2023-11-05 19:00:15.477 - audio - ovos_utils.gui:_pages2uri:823 - ERROR - Unable to find page: PlayerLoader
Nov 05 19:00:15 mycroft ovos-audio.sh[1614]: 2023-11-05 19:00:15.481 - audio - ovos_utils.file_utils:resolve_resource_file:153 - WARNING - Deprecation version=0.1.0. Caller=ovos_utils.gui:812. Expected a dict config and got None.
Nov 05 19:00:15 mycroft ovos-audio.sh[1614]: 2023-11-05 19:00:15.491 - audio - ovos_utils.file_utils:resolve_resource_file:153 - WARNING - Deprecation version=0.1.0. Caller=ovos_utils.gui:813. Expected a dict config and got None.
Nov 05 19:00:15 mycroft ovos-audio.sh[1614]: 2023-11-05 19:00:15.500 - audio - ovos_utils.gui:_pages2uri:823 - ERROR - Unable to find page: SuggestionsView
Nov 05 19:00:15 mycroft ovos-audio.sh[1614]: 2023-11-05 19:00:15.619 - audio - ovos_plugin_common_play.ocp.media:handle_track_state_change:512 - INFO - TrackState changed: <TrackState.PLAYING_AUDIOSERVICE: 21>
Nov 05 19:00:15 mycroft ovos-audio.sh[1614]: 2023-11-05 19:00:15.751 - audio - ovos_plugin_common_play.ocp.media:handle_track_state_change:512 - INFO - TrackState changed: <TrackState.QUEUED_AUDIOSERVICE: 31>
Nov 05 19:00:15 mycroft ovos-audio.sh[1614]: 2023-11-05 19:00:15.823 - audio - ovos_audio.audio:_stop:257 - INFO - END Stop
Nov 05 19:00:15 mycroft ovos-audio.sh[1614]: 2023-11-05 19:00:15.970 - audio - ovos_plugin_common_play.ocp.media:extract_stream:461 - INFO - OCP plugins metadata: {'uri': 'https://yleradiolive.akamaized.net/hls/live/2027676/in-YleKlassinen/abr.smil/chunklist_b256000_ao.m3u8'}

One fix is to disable MPRIS by adding "disable_mpris": true to the config. The easiest way to do this is to find the config file in the ~/.config/mycroft/mycroft.conf and make sure the following section is present:

{
  "Audio": {
    "backends": {
      "OCP": {
        "type": "ovos_common_play",
        "disable_mpris": true
      }
    }
  }
}

This does not fix the root cause, but it does stop the looping and allows the audio service to play media.