[Bug: 21.4.19] XEmacs Sounds Modulate System Volume Under Alsa and FC4

[Randy Yates]

Jerry James <james at xemacs.org> writes:

> Hi Randy,

Hi Jerry,

> Sorry for the delay.  We had a minor problem that held up the mailing
> lists for a little bit.

No problem.

> Randy Yates <yates at ieee.org> wrote:
>> Everytime XEmacs plays a sound, the Alsa mixer volume is increased
>> momentarily for the duration of the sound (e.g., drum, whip, etc.).
>> This causes the volume from other PCM music sources (e.g., the xmms
>> player) that may be active at the time to be modulated up and
>> down. The amount of the volume change is significant and is very
>> irritating. This behaviour also makes the sound XEmacs is playing very
>> loud, in addition to increasing the volume (momentarily) of the other
>> PCM sound sources.
>>
>> Specifically, if you start the gnome-volume-control application to
>> monitor the mixer settings, you will find under the playback tab there
>> are two volume sliders: Master and PCM. When XEmacs emits a sound, you
>> can visually see the PCM volume being momentarily increased. (If the
>> sound is short, a change in the slider position may not happen every
>> time the sound is played - try it several times). 
>>
>> If you could look into this and repair it, or give me suggestions
>> on how it can be avoided, I would be thankful.
>
> Well, doggone.  This is what I get for trying to get sound working on
> Fedora Core 5.  I'm the one who stuck you with this horrible behavior,
> Randy.  I'll try to fix it.

No problem - this is FREE, and you're working for FREE, so I have no
complaints - only thank yous.

> I wrote the code trying to cope with the sound interface's volume
> parameter.  I thought the mixer was the right way to deal with it.
> Apparently not.  If any gnomes in the woodwork know how to set the
> volume for one particular sound only, please sprinkle your magic pixie
> dust on me.
>
> Otherwise, I'll have to resort to reading documentation!

If you're asking me how to interface to the Linux/FC4 sound API, I
have no idea. But if I needed to find out, the first place I'd
probably look is in the source code for Audacity, an open-source sound
editor based on wxWidgets. Or perhaps it is built into wxWidgets
themselves. I'd start either of these two places.

--Randy


-- 
%  Randy Yates                  % "Though you ride on the wheels of tomorrow,
%% Fuquay-Varina, NC            %  you still wander the fields of your
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%%%% <yates at ieee.org>           % '21st Century Man', *Time*, ELO
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