[pulseaudio-discuss] pulseaudio elusive

Jack Tanner ihok at hotmail.com
Sun Dec 7 06:55:58 PST 2008

Colin Guthrie <gmane <at> colin.guthr.ie> writes:

> Well the main tool that is used when you have PA underneath is 
> pavucontrol. This app will allow you to work with all your currently 
> running streams and allow you to change the device they use etc. Once 
> you change this setting it should be remembered from then on (e.g. pulse 
> will know that VLC prefers to be on the Audigy, MythTV prefers the VIA etc.)

Whoa! Colin, thank you, that just turned on so many lightbulbs. I'd run
pavucontrol a bunch of times, but nothing seemed incorrect from just looking at
the GUI. Following what you just said, I ran it with sound actually playing in
vlc at the same time, and lo! more stuff showed up. This was completely
non-obvious to me, that to make pavucontrol do anything, you had to have a
stream going at the same time.

> pavucontrol also let's you set the "default" sink, so that brand new 
> streams will go through your preferred device by default. This does not 

I tried to look for that in pavucontrol, found nothing, and then ... The second
lightbulb was that right-clicking on this in pavucontrol would be a good idea.
Again, completely unexpected. Right-clicking, in my experience, is usually used
in editing docs (OOO, GIMP, Inkscape, etc.), but not in "control panel" kinds of

> apply to applications that have already played as they will be 
> remembered as perfering the device they were first played on (IMO this 
> is suboptimal and there should be a concept of "default" built in to the 
> stream remembering stuff - this will come eventually I'm sure).

Lightbulb 3! Where is this state saved? Is it a specific file in ~/.pulse?

> VLC now has a pulse output module. I'm not sure if that is the official 
> version nor if it is part of the vlc package on F10, but I'd imagine so.

Yup, it's in there.

> Also there is a patch for MythTV that adds pulse support too (I rediffed 
> it recently).
> http://svn.mythtv.org/trac/ticket/5473
> Also in order to get pulse to do multichannel you have to set the 
> channels to 6 (for 5.1) in your /etc/pulse/daemon.conf (there may be a 
> config program to do this in F10, I'm not familiar with it - we have a 
> GUI in Mandriva I know that much :))

Aha! I'll look at daemon.conf. 

What's the GUI in Mandriva? Is it not upstream? ;)

So, gnome-sound-properties shows the Audigy2 as having 3 outputs:

ADC Capture/Standard PCM Playback (ALSA)
Multichannel Playback (ALSA)
Multichannel Capture/PT Playback

When I tell g-s-p to use Standard PCM, it says:

audiotestsrc wave=sine freq=512 ! audioconvert ! audioresample ! gconfaudiosink
profile=music: Could not open audio device for playback.

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