[pulseaudio-discuss] pulseaudio elusive

Colin Guthrie gmane at colin.guthr.ie
Sun Dec 7 09:16:26 PST 2008

'Twas brillig, and Jack Tanner at 07/12/08 14:55 did gyre and gimble:
> 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.

Yeah, I think more needs to be done here to make it more obvious. In 
actual fact a usability "improvement" was to default to the "Sinks" tab 
if no streams are running, but in actual fact if it started with a blank 
pane and some text saying "No active streams. This pane will list blah, 
blah blah" would actually be better for first time users etc.

>> 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
> places.

Well there is a little drop down thing that you can use without right 
clicking but I agree it's non-obvious.

The main trouble is there are not enough volunteers pushing this app 
forward (or creating other apps).

>> 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?

Yeah, although the format is not meant to be human friendly... 
eventually this should be exposed via some kind of editor but we need to 
  change the protocol to do this. Arguably it should not be stored in 
~/.pulse either but rather inside the XGD ~/.config tree.

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

It's not a patch to the upstream apps otherwise I would have pushed it 
already :) We have drakconf which is our configuration system and as 
part of that there is draksound which has the gui to enable pulseaudio 
and alsa routing and the 5.1 setting too.

> 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.

gnome-sound-properties should just be told to use PulseAudio. You 
basically want to offload all sound libraries (and gnome-sound-settings 
is really just a frontend to the gstreamer library really) to use their 
Pulseaudio outputs. After that you just use pavucontrol to control 
everything related to which device to use.

So in my setup I have just about everything set to Autodetect and it 
automatically uses pulse.



Colin Guthrie

Day Job:
   Tribalogic Limited [http://www.tribalogic.net/]
Open Source:
   Mandriva Linux Contributor [http://www.mandriva.com/]
   PulseAudio Hacker [http://www.pulseaudio.org/]
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