[pulseaudio-discuss] Pulseaudio 0.16-test4 - my experience

Maxim Levitsky maximlevitsky at gmail.com
Mon Aug 10 14:48:20 PDT 2009

On Mon, 2009-08-10 at 22:25 +0200, Lennart Poettering wrote:
> On Fri, 07.08.09 02:51, Maxim Levitsky (maximlevitsky at gmail.com) wrote:
> > 
> > On Thu, 2009-08-06 at 17:06 +0300, Maxim Levitsky wrote:
> > > So I carefully set everything up for it, and it now works (except 32 bit
> > > compat libraries for skype )
> > > 
> > > Speaking of 32 bit compat libraries, is there a tutorial how to compile
> > > these? (It isn't trivial, since I need alsa, pa libraries and plugins
> > > for alsa)
> > > 
> > > 
> > > 1 - all sounds played through libcanberra (using pulse backend) (which
> > > was installed from source (everything from latest git branches), play on
> > > right speaker only, and this is confirmed by pavucontrol which display
> > > the volume for notify sound briefly (which I consider a bug on its own,
> > > because this makes it impossible to change a stream location - clicking
> > > on the stream chooser button, takes focus out of it, thus prevents
> > > device list from being shown)
> > > It displays "front right"
> > Small progress, this only happens with pulse backend of canberra, which
> > isn't used in 9.04, which explains why I see that bug now.
> > It is probably the canberra bug, maybe it doesn't tell pulse that sound
> > is mono? (I think that notify sounds are mono)
> Hmm, Ubuntu didn't use the pa backend for libcanberra? Oh my!
> Hmm, we had some recent changes in the surround sound handling in
> libcanberra. Which version are you running?

I pulled it from git repository.

git log

commit 605aee559f5bd6d53c4c93a9c3bbeefdcf10cad2
Author: Lennart Poettering <lennart at poettering.net>
Date:   Wed Aug 5 03:19:44 2009 +0200

    prepare release 0.15

commit 593511bad132e0d262780918cce469ad69804b52
Author: Lennart Poettering <lennart at poettering.net>
Date:   Tue Aug 4 01:55:53 2009 +0200

    gtk: don't take gdk lock since it is not recursive and it might
already be taken

> > > 2 - flat volumes are evil. It feels like a feature being removed. Now
> > > changing a volume for a stream directly affects main volume, and alsa
> > > volume through it.
> > > I though that one of main PA features, was a volume control per stream.
> > > Could you explain me what flat volumes are (I know that turning them off
> > > fixes this issue)?
> > 
> > Just one issue though. If a stream is played at low volume, and I click
> > a button, a noise sound is emmited and it almost covers the notify
> > sound.
> > maybe this is a HW fault, or I suspect that PA reconfigures the played
> > sound to play at lower volume, and this gives that noise sound. Anyway
> > this is a bug.
> I don't follow. Could you explain this again?

Let say I start a music player, and set its PA stream volume to low
(rhythbox for example does that)

Now I click on a button.

Now what happens:

1 - PA sets hardware volume to high
2 - PA lowers music stream volume to low, so it plays at same volume.
3 - PA plays the notify sound.

What is wrong is that the above sequence triggers a short noise, which
origin isn't yet known to me (also it is possible to hear the music at
high volume for a moment).

Since the notify sound is itself very short, it is almost replaced by
this noise.

It is ether a hick-up in PA, while it changes the stream volume, or a
hardware problem.

I do like the idea of flat volumes though, this is quite right, and nice
addition. However in case this is a hardware fault, I think that final
volume of a card should also be software one, and hardware volume set to

I don't know about this sound codec, but I do know that many sound cards
like to emit all kinds of noises, when their volumes are touched. 

On one hand, when the user  touches the master volume, he can expect
noises, but on the other hand when software like PA does, it is a
different story.

Best regards,
	Maxim Levitsky

> Lennart

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