[LAU] How to combine microphone audio and music from application to pipe to video conference

[Samir Parikh]

Hello,

I am trying to combine the audio from my microphone (either built in
microphone from my laptop or bluetooth headset) with music playing
from Rhythmbox Music Player running on Ubuntu 16.04 and pipe that as
the audio input to video conference services such as Jitsi.

I don't know much about Linux audio internals and wasn't sure how to
do this.  Can I do this completely via the operating system using
Pulse Audio?  Do I need to do something with Jack?  Or do I need
specialized software such as OBS, Ardour or Reaper?

Any help or suggestions on pointing me in the right direction or how
to get started would be greatly appreciated.  I'm hoping that I can do
this completely through software without external hardware such as a
mixer or something.

Thanks in advance.

Samir