Status/Audio

Current status

• We have yet to figure out device policies: what to do on jack unplug, what to do on jack plug while listening to music, what to do on jack unplug when you're on a phone call, etc.

Development notes

For each device, we'll need to create usable Alsa UCM files. And we'll need to learn a bunch about pulseaudio's routing and policy management, how to act on certain plug events, etc.

Unsorted (useful) links:

• https://www.systutorials.com/docs/linux/man/1-alsaucm/
• https://github.com/alsa-project/alsa-ucm-conf
• https://wiki.postmarketos.org/wiki/Alsa_UCM
• https://wiki.archlinux.org/index.php/PulseAudio/Examples
• https://unix.stackexchange.com/questions/115302/disable-headphone-jack-detection-in-pulseaudio
• https://wiki.merproject.org/wiki/Nemo/Audio
• (Fremantle/N900-specific) http://wiki.maemo.org/Porting/Audio/Q_and_A_RE-PA
• (Fremantle/N900-specific) https://blog.linuxplumbersconf.org/2009/slides/Jyri-Sarha-audio_miniconf_slides.pdf

Some more, not deduplicated with above list:

• https://github.com/werman/noise-suppression-for-voice
• https://fossies.org/linux/pulseaudio/src/modules/echo-cancel/webrtc.cc
• https://lists.freedesktop.org/archives/pulseaudio-discuss/2017-May/028188.html
• https://wiki.archlinux.org/title/PulseAudio/Troubleshooting#Audio_quality
• https://www.reddit.com/r/linux/comments/2yqfqp/just_found_that_pulseaudio_have_noise/
• https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/issues/196
• https://github.com/werman/noise-suppression-for-voice
• https://www.linuxuprising.com/2020/09/how-to-enable-echo-noise-cancellation.html
• https://github.com/baresip/baresip/wiki/Using-PulseAudio:-module-echo-cancel
• https://blog.linuxplumbersconf.org/2009/slides/Jyri-Sarha-audio_miniconf_slides.pdf

• https://git.sailfishos.org/mer-core/pulseaudio-modules-nemo/tree/master/src/music
• https://git.sailfishos.org/mer-core/pulseaudio-policy-enforcement
• https://github.com/nemomobile/policy-settings-basic
• https://github.com/nemomobile/pulseaudio-settings-n900
• https://github.com/nemomobile/pulseaudio-module-cmtspeech-n9xx/commits/master
• https://wiki.merproject.org/wiki/Nemo/Audio
• http://wiki.maemo.org/Porting/Audio/Q_and_A_RE-PA

• https://github.com/baresip/baresip/wiki/Using-PulseAudio:-module-echo-cancel