[pulseaudio-discuss] How to combine microphone audio and music from application to pipe to video conference

[Samir]

Sean Greenslade wrote on 5/16/20 1:23 AM:

> Pulse has two types of sound devices, sources and sinks. Sources are
> input devices like microphones. Sinks are output devices like speaker or
> headphone ports. Programs that work with sound can attach to sources in
> order to pull sound in, and can attach to sinks to output sound. I
> suggest playing around with the "pavucontrol" utility to see what
> sources and sinks are present on your machine. It also shows what
> applications are recording or playing back audio, and allows you to
> redirect existing audio streams on the fly. It's quite handy.
> 
Sean,

Thanks so much for your quick and detailed reply to my post (and 
apologies for taking so long to respond!).

I'm still trying to wrap my head around your steps but am encouraged 
that this may be possible with just Pulse Audio and no external hardware.

When I run "pavucontrol" with Rhythmbox playing music, here is what the 
"Input Devices" tab looks like with "All Input Devices" shown: 
https://imgur.com/a/kSth4O1

The "Monitor of Built-in Audio Analog Stereo" input corresponds to the 
music coming from Rhythmbox.  The "Built-in Audio Analog Stereo" is my 
laptop's built-in microphone.

Given that, do I still run your two commands to create the "virtual mixer"?

$ pacmd load-module module-null-sink sink_name=virt_mix
$ pacmd update-sink-proplist virt_mix device.description=VirtualMixer

While I'm comfortable on the command line, I don't know anything about 
Pulse Audio so just wanted to double-check and take this step-by-step.

Thanks
Samir