#831 PA_PROP_MEDIA_ROLE causes unexpected results


Normally, I'd provide a summary, but this bug is best described by a how-to-reproduce section.

How to reproduce

Build latest Mumble (git describe says it's 1.2.3-184-gae54c0c) on Linux (Fedora 15 x86_64 here).

  1. Start Rhythmbox playing your favorite music
  2. Open Mumble.
  3. Set to "Attenuate applications by..." to 60% or something similar
  4. Set "while you talk" so you talking will cause attenuation
  5. Save settings.
  6. Speak!

What is expected

I expect Rhythmbox to continue playing, but become much quieter when I start speaking.

What actually happens

Rhythmbox mutes itself once Mumble opens! It unmutes itself when Mumble is closed.


The simplest workaround is to manually force Rhythmbox to play. Once it starts playing, things work as intended.

Why this occurs

Rhythmbox is trying to respect a Pulseaudio setting. Mumble, as of git revision 1.2.3-58-ge6831d8, identifies itself as a phone application (see src/mumble/PulseAudio.cpp, line 115). Rhythmbox mutes itself as long as the "phone" audio is alive.

Why it's not Rhythbmox's fault

Rhythmbox is perhaps overzealous in muting itself so suddenly, but I think this is the correct behavior; if I received a call, I'd want my music to pause and mute. However, there's two reasons why this is Mumble's fault:

  1. People can be on Mumble for long periods without actually talking to anyone. Put simply, Mumble is much more asynchronous than any phone call.
  2. Mumble, with its recent Pulseaudio attenuation support, introduced in revision 1.2.3-181-g0e4d963, provides a much more elegant way to handle what is intended here.

This mess is possibly a Pulseaudio missing feature more than anything else, but for the time being, Mumble should probably be more conservative with its role, lest more apps mistake a Mumble chatroom for a phone call.


  • Mr. Rawnar

    Mr. Rawnar - 2012-01-02

    What is your suggestion of being a good media.role for mumble?

  • Colomban Wendling

    I'm not 100% sure it's the exact same problem, but since recently (since my distro, Debian Sid, upgraded to PulseAudio 2.0 I think) whenever I start Mumble, Rhythmbox gets muted. This is the same as the original report, with one interesting detail: I have the settings for changing other application volumes when speaking/listening turned off.

    If I unmute Rhythmbox manually it starts playing fine again, but until an unrelated event sound (any sound tagged as event) is played. For example, if my systems emits a bell sound when Mumble is running, Rhythmbox gets muted and paused, and I need to unmute and restart manually. However, this doesn't happen if Mumble isn't running.

    I'm not 100% sure who's fault it is, but it's definitely weird and annoying. I usually leave Mumble open and simply mute both input and output when I don't wanna speak or listen, but it's not really possible anymore.


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