RE: [linux-audio-dev] suggestion for developers: "real" quad-chan nel output on an SBlive

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Subject: RE: [linux-audio-dev] suggestion for developers: "real" quad-chan nel output on an SBlive
From: STEFFL, ERIK *Internet* (SBCSI) ("STEFFL,)
Date: Wed Nov 21 2001 - 23:03:57 EET


> -----Original Message-----
> From: D. Stimits [mailto:stimits_AT_idcomm.com]
> Sent: Wednesday, November 21, 2001 11:17 AM
> To: linux-audio-dev_AT_music.columbia.edu
> Subject: Re: [linux-audio-dev] suggestion for developers: "real"
> quad-channel output on an SBlive
>
>
> "STEFFL, ERIK *Internet* (SBCSI)" wrote:
> >
> > > -----Original Message-----
> > > From: Josh Whiting [mailto:jwhiting_AT_hampshire.edu]
> > >
> > > i am a list-lurker, primarily a windows multimedia user,
> but with an
> > > interest in audio software development and hence an
> interest in linux.
> > >
> > > anyway, i have and idea that has been provoked by my recent
> > > explorations
> > > into quad-channel audio output. Basically, the idea is to
> > > write a driver to
> > > interface with the SB-Live EAX bus that converts the SB
> live into a
> > > more-or-less 'true' four channel output device. How? 1 -
> > > setup two stereo
> > > virtual audio input ports, 2 - assign each channel a status
> > > in the EAX bus
> > > as a sound source with a specific spatial position so as to
> > > emulate the
> > > direct dispatch of each channel to its respective output in
> > > the dual-output
> > > SB live DACs. You may not even need two virtual ports,
> as you could
> > > probably assign the main output (sb live wave out) to the
> front stereo
> > > outputs and then just send the second (virtual) stereo stream
> > > to the rear
> > > outputs.
> > >
> > > and bam - the SB live is now a (low cost) four channel
> output device,
> > > overcoming the (idiotic, painful) limitations imposed by
> creative's
> > > engineering of the board only support a single stereo output
> > > even though the
> > > card has two of them...
> >
> > ?
> >
> > sb live provides 5.1 output under windows (you can set
> output under
> > speakers in eax control center (headphones, two speakers, 4
> speakers, 5.1
> > speakers), there's also a demo for that somewhere there).
> Not sure how it
> > works under linux (I don't have linux installed on that
> computer yet).
>
> EAX is proprietary. It isn't available under Linux, and
> unlikely it ever
> will. The OpenAL code is probably the closest you'll see in the near
> future, but something of a similar idea could probably be used there
> (just not EAX).

  aha. but if eax can do it then there has to be hw that supports it, right?
otherwise eax would be able to output 5 separate channels (and it does, even
though I don't know how well separated they are). the original post was
talking about more-or-less true 4 channel and I was saying that 5 channel
output is possible (using sb live HW, there might be software issues
involved that are not easy to solve).

  or are you saying that using information available to opensource
developers it is not possible to use the same HW that eax uses?

        erik


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