Full Duplex (Play + Record simultaniously)

Full Duplex (Play + Record simultaniously)

[Georg Wendt]

Hello,

I wanna use a record-programm running in one shell and playback audio
started on another shell.
However, whenever one of the programs has started, it blocks the
dsp-device and the other application can't work.
Is there a way to avoid this effect?
Since I work on the sourcecode of the player and the recorder, I don't
care if there's a solution where I need to set some sort
Systemparameters...

Another way: What about using two soundcards, one for playback, the
other for recording? Since I can decide the sound-device used by the
applications, this should work, shouldn't it?

Thanx a lot for any answer!!! :-)

Ciao Georg

Re: Full Duplex (Play + Record simultaniously)

[Raoul Boenisch]

On Wed, 3 Mar 1999, Georg Wendt wrote:

> Another way: What about using two soundcards, one for playback, the
> other for recording? Since I can decide the sound-device used by the
> applications, this should work, shouldn't it?

Yes, it works. I did it with an sb16 and a spea media fx.

--
Raoul Boenisch, Winkhauser Talweg 165, 45473 Muelheim an der Ruhr, Germany
homepage: http://www.raoul.home.pages.de/       home phone: +49 208 764257

Re: Full Duplex (Play + Record simultaniously)

[Thomas Sailer]

Georg Wendt wrote:

> I wanna use a record-programm running in one shell and playback audio
> started on another shell.
> However, whenever one of the programs has started, it blocks the
> dsp-device and the other application can't work.

Depends on the soundcard and the driver. With some drivers this works.

> Is there a way to avoid this effect?

Yep - don't access the audio device directly, use an intermediate
program. EsounD might provide what you need.

> Another way: What about using two soundcards, one for playback, the
> other for recording? Since I can decide the sound-device used by the
> applications, this should work, shouldn't it?

In this case you get plesiochronous sampling rates. If that is a
problem depends on the application.

Tom

Re: Full Duplex (Play + Record simultaniously)

[Eric B. Mitchell]

Thomas Sailer wrote:
> 
> Georg Wendt wrote:
> 
> > I wanna use a record-programm running in one shell and playback audio
> > started on another shell.
> > However, whenever one of the programs has started, it blocks the
> > dsp-device and the other application can't work.
> 
> Depends on the soundcard and the driver. With some drivers this works.
> 
> > Is there a way to avoid this effect?
> 
> Yep - don't access the audio device directly, use an intermediate
> program. EsounD might provide what you need.

The OSS drivers allow full duplex operation on some sound cards.
My SB AWE 32 works great for it.  EsounD will use it if it's 
available, but I'm not sure how robust the error handling is
should the full duplex operation fail (haven't had the problem
myself =).

> > Another way: What about using two soundcards, one for playback, the
> > other for recording? Since I can decide the sound-device used by the
> > applications, this should work, shouldn't it?
> 
> In this case you get plesiochronous sampling rates. If that is a
> problem depends on the application.

plesiochronous? i assumes that translates roughly into "skewed data"?

> Tom

-- ebm
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| Eric B. Mitchell         mailto:ericmit@ix.netcom.com |
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=+

Re: Full Duplex (Play + Record simultaniously)

[Thomas Sailer]

"Eric B. Mitchell" wrote:

> The OSS drivers allow full duplex operation on some sound cards.
> My SB AWE 32 works great for it.  EsounD will use it if it's
> available, but I'm not sure how robust the error handling is
> should the full duplex operation fail (haven't had the problem
> myself =).

You've got the source for EsounD, you can improve the situtation 8-)

> plesiochronous? i assumes that translates roughly into "skewed data"?

The sampling rates are slightly different, thus sliding about each
other. If you don't do any corrective measures, you'll either
get buffer overruns or underruns.

Tom