pulseaudio – Fixing Volume Changes After Plugging USB Camera or Changing Playback


When I plug in a USB camera then the volume levels are changed to some preset values. It also happens sometimes when I start some audio playback from a different SW (e.g. radiotray or mplayer). I don't want this automatic volume changing. I have XUbuntu 14.04 and I suspect PulseAudio but I can't figure out how to disable it.

Best Answer

Stream output volume is a feature which allows individual stream properties based on applications.

For streams it is controlled by the pulseaudio module module-stream-restore, for audio devices it is controlled by module-device-restore, and for sound cards (if multiple) it is module-card-restore.

To test whether our issue is resolved we can temporarily unload any of these modules (which should be loaded from our default.pa), e.g.:

pacmd unload-module module-stream-restore

The module will be re-loaded by restarting the pulseaudio sound server with

pulseaudio -k

If after unloading the issue was resolved we can prevent loading this module by commenting out the line in our default.pa (located in /etc/pulse/, ~/.pulse/, or ~/.config/pulse/ like this:

#load-module module-stream-restore