[LAU] How to prevent applications from changing my mic level?

[Len Ovens]

On Wed, 6 May 2020, S. wrote:

> So you seem to be suggesting that Pulse is directly responsible for
> manipulating the levels? I assumed that it was Chromium and its spinoffs
> (Chrome and Electron apps), using an AGC function specifically as part of
> the WebRTC protocol:

Pulse poses as an alsa device to the application so that more than one 
application can use the same device at the same time. So chrome controls 
it's device which is pulse and pulse satisfies the request with either 
direct device manipulation or digital if direct is not possible (or if 
there is more than one application using that device).

> Thanks for confirming this option, I had found a similar suggestion here:
> https://askubuntu.com/questions/689209/how-to-disable-microphone-volume-auto-adjustment-in-cisco-webex/761103#761103
> That looks like the solution I was hoping for of making it not possible for
> processes to mess with the mic gain. But unfortunately the profiles are
> under /usr/share/ , so the tweaks will be reverted every time Pulse is
> updated... :-(

As with all things Linux these days, configuration can be done in more 
than one place. While I am sure that an added profile file with a unique 
name would not interfere with upgrades even in /usr/share, quite probably 
the default profile could be overridden in /etc/pulse/*/ and failing that, 
there is always ~/.local/share/ to play with. Really, it is all about 
seaking documentation and examples to work from. If you only have one user 
on the system, copying the file from:
/usr/share/pulseaudio/alsa-mixer/paths/analog-input-internal-mic.conf
to:
~/.local/share/pulseaudio/alsa-mixer/paths/analog-input-internal-mic.conf
and editing it there may be just as effective.

As before, I have not personally tried this as jack already fixes it for 
me.

--
Len Ovens
www.ovenwerks.net