Re: [linux-audio-user] sharing /dev/dsp between apps

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Subject: Re: [linux-audio-user] sharing /dev/dsp between apps
From: Robert Jonsson (robert.jonsson_AT_dataductus.se)
Date: Wed Feb 06 2002 - 09:19:55 EET


Hello Matthew,

matthew yee-king wrote:

> hello
>
> i took the plunge and installed alsa then i tried to run two oss apps
> using the alsa emulated /dev/dsp and it doesn't like to share :( ah
> well.... works fine for one though.
>
> i'm using the alsa 0.9.0beta10 ens1370 driver on my creative pci128. i
> guess that means my hardware can't handle multiple streams. can
> several alsa native apps talk to the same sound card using software
> based multiple streams?

ens1370 does indeed not mix several streams in hardware. I think there
has been talk (and some implementation) of a software mixer for alsa,
providing mixing possibilties for all cards that connect to alsa. As
I've understood it this is not finished.

>
> I can't get the alsaout xmms output plugin to work at the moment so i
> can't try running xmms native in alsa and running the other app using
> dev/dsp. (which was my backuo plan...).

>
>
> in my fiddling i noticed another thing - the esd don't work any more.
> does anyone know anything about that? what is esd used for... do i
> care if i have alsa and oss emulation running and i use sawfish as my
> window manager?

I think I, at onetime have been running esd under alsa oss
compatibility... what is the error?

Esd is used for instance by Gnome as a generic means for mixing sound.
KDE uses Arts for pretty much the same thing.
I don't think the sawfish window manager cares at all... If you are
infact running Gnome programs these will however not output any sound
(alarm bells and such...).
If you have the possibility to run Arts I think you might get things to
work by using the artsdsp, or the never approach with a arts kernel
module which emulates oss (only available with kde3 and cvs I think).

Regards
/Robert

>
>
> bye
>
> matthew
>
>
> On Tuesday, February 5, 2002, at 06:35 PM, Nelson Posse Lago wrote:
>
>> On Thu, Jan 31 2002 at 11:41:10am +0100, Jörn Nettingsmeier wrote:
>>
>>> Paul Winkler wrote:
>>>
>>>> AFAIK, alsa alone doesn't do this. You need some kind of "soft mixer"
>>>> - a sound daemon such as esd or artsd.
>>>
>>> i vaguely remember it *is* possible with alsa
>>
>>
>> I made a similar question some time ago, and Paul Davis answered me that
>> it *is* currently possible with ALSA *if* the hardware supports it, and
>> that it *may become* possible to do it on the driver or library level in
>> the future.
>>
>> Hope this helps,
>> Nelson
>>
>


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