Wine and PulseAudio

[Tomas Carnecky]

Jan Zerebecki wrote:
> On Sun, Feb 24, 2008 at 12:05:46PM +0100, Tomas Carnecky wrote:
>> All wine apps are identified as 'ALSA plug-in [wine-preloader]' in the 
>> PA daemon, so you can't set per-app volume and sinks since all wine apps 
>> show up under the same name. That is a technical limitation of the alsa 
>> plugin and can't be fixed (well, unless the plugin does some /proc/self 
>> voodoo to extract the true name). However that does not make the plugin 
>> unusable, but per-app settings is a major functionality of PA, so it's 
>> kind of bad if that doesn't work.
> 
> I'm not sure if /proc/self is the right way to implement this but
> in some way it should be made possible with the alsa->PA plugin.
> 
> (Why isn't the changed process name used, that is also shown by
> ps? Perhaps it should be implemented by using a environment
> variable and/or argument to the alsa->PA plugin, that would also
> allow the following feature?)

http://www.pulseaudio.org/browser/trunk/src/pulse/util.c#L160

Basically uses readlink("/proc/self/exe") and if that fails the falls 
back to prctl(PR_GET_NAME).

> Does PA (when used "directly") also always use the original
> process name? I imagine I'm not the only one who would want to
> have a bit more configurability there (some processes with the
> same executable should probably not share the same settings and
> the other way around).

When a PA client connects to the daemon it can specify the context name 
(a name identifying the application) and each stream also has a name 
(the alsa pulse plugin sets that to "PCM Playback" for playback streams).
Each client can choose its own name, the alsa pulse plugin extracts the 
name like described above, applications that use PA natively usually 
choose a fixed name: mplayer uses "MPlayer", netscape flash uses "Adobe 
Flash" etc.

>> I have gotten winealsa to work with a patched alsa pulse plugin, but 
>> whether my patch will be accepted remains uncertain. There are some 
>> fundamental differences between ALSA and PA, for example ALSA uses 
>> frames and PA uses microseconds and I suspect there are rounding issues 
>> involved that make winealsa hang in certain situations. I'll need some 
>> help from the PA developers to fix that, but so far it's been quite 
>> difficult to get hold of them.
> 
> We should really get those things that are wrong in either
> winealsa or PA fixed. (Assuming the PA developers are interested...)
> 
> AFAIK bug #10942 and at least the part of bug #10910 about "Could
> not find 'PCM Playback Volume' element" are things that need
> fixing in winealsa.

See http://www.pulseaudio.org/ticket/198 what the pulse devs think of 
that issue.

tom