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

[Martin Desrumaux]

On 16/05/2020 07:25, Len Ovens wrote:

> On Fri, 15 May 2020, Samir Parikh wrote:
>
>> 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?
>
> OBS is probably the easiest way. You can add your local video if 
> needed as well. OBS will work fine with just pulse or jack. I don't 
> know much about jitsi it self but if it uses pulse as the default 
> device there should be no problem.

I'd also look towards OBS solution.

In the previous week, I was looking for streaming both video and audio 
from OBS Studio to Jitsi.
I found this Github thread: 
https://github.com/CatxFish/obs-virtual-cam/issues/17

For the video, you can use the following OBS plugin: 
https://github.com/CatxFish/obs-v4l2sink
This plugin uses the v4l2loopback kernel module.

For audio, some user suggested to create a virtual sound card with `sudo 
modprobe snd-aloop`.
See this comment: 
https://github.com/CatxFish/obs-virtual-cam/issues/17#issuecomment-514565571

With this solution, you should be able to configure volumes of "Desktop 
Audio" and "Mic/Aux" in OBS's Audio Mixer and stream it to ffmpeg which 
forward the stream to the virtual audio card.
Then, you can use the virtual audio card as your microphone in Jitsi or 
any other software / web app.

However, this solution may have latency. If you need low latency, I 
guess that you'd need to ditch ffmpeg and use Jack instead of pulseaudio 
but I'm not sure which way to go.

Hope it helps :)

>
>
> -- 
> Len Ovens
> www.ovenwerks.net
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