Recording Both Microphone and Speaker Under Ubuntu 21.04

When one records audio under Linux, issue that quite a few applications have is recording both microphone input and headphone output. And that's true for SimpleScreenRecorder, otherwise really good recording application.

However, Linux always has a way around those restrictions and those can be actually found on SimpleScreenRecorder pages if you look deep enough.

Terminal  Copy
pactl load-module module-null-sink \
  sink_name=duplex_out sink_properties=device.description="\"Duplex\ Output\""
pactl load-module module-null-sink \
  sink_name=app_out sink_properties=device.description="\"Application\ Output\""
pactl load-module module-loopback source=app_out.monitor
pactl load-module module-loopback source=app_out.monitor sink=duplex_out
pactl load-module module-loopback sink=duplex_out
pactl set-default-sink app_out

Trick is to essentially create two new output devices (i.e. sinks). One of them (app_out) will just be a target toward which applications should direct their output. Magic happens with the second output (duplex_out) which combines application output and what comes from microphone.

Now when you record audio, you can just point application to Duplex Output and record both sides.

PS: To make these changes permanent, they can be entered into /etc/pulse/default.pa. Of course, quoting rules are bit different so adjust accordingly if you have a space in your description.

/etc/pulse/default.pa  Copy
…
# Recording setup
load-module module-null-sink sink_name=duplex_out sink_properties=device.description="Duplex\ Output"
load-module module-null-sink sink_name=app_out sink_properties=device.description="Application\ Output"
load-module module-loopback source=app_out.monitor
load-module module-loopback source=app_out.monitor sink=duplex_out
load-module module-loopback sink=duplex_out
set-default-sink app_out