stt

listen on linux

https://wiki.archlinux.org/title/PulseAudio/Examples

10. ALSA monitor source

To be able to record from a monitor source (a.k.a. "What-U-Hear", "Stereo Mix"), use pactl list to find out the name of the source in PulseAudio (e.g. alsa_output.pci-0000_00_1b.0.analog-stereo.monitor). Then add lines like the following to /etc/asound.conf or ~/.asoundrc:

pcm.pulse_monitor {
  type pulse
  device alsa_output.pci-0000_00_1b.0.analog-stereo.monitor
}

ctl.pulse_monitor {
  type pulse
  device alsa_output.pci-0000_00_1b.0.analog-stereo.monitor
}

Now you can select pulse_monitor as a recording source.

Alternatively, you can use pavucontrol to do this: make sure you have set up the display to "All input devices", then select "Monitor of [your sound card]" as the recording source.

$ pactl list | grep -A 50 RUNNING | grep -E 'RUNNING|Name:|Monitor Source:' | grep Monitor.Source | head -n 1 | awk '{print $NF}'