Subject: RE: [linux-audio-dev] suggestion for developers: "real" quad-channel output on an SBlive
From: Ivica Bukvic (ico_AT_fuse.net)
Date: Thu Nov 22 2001 - 10:28:03 EET
There is a way of pointing to all 4 channels in Windows by installing
EMU APS drivers for sblive (and thus trashing the eax support, but at
least you'll get sub 20ms latency in windows with a creative card, which
is probably as good as it gets), and using the ASIO driver that comes
with that one + Cubase or something similar that can use ASIO in an
efficient manner. For more info on the driver go to:
http://come.to/sblive
As far as the linux is concerned, I've heard that /dev/dsp0 points to
front stereo, while dev/dsp1 to the rear stereo, but never got to test
this one out, and am not sure whether the issue pertains to alsa or oss
drivers (or both), neither do I know how good it is (last time I checked
the back stereo was mirrored front, nothing more). I'd suggest visiting
emu10k1 linux mailing list (forgot the URL, but remember it being named
emu10k1-devel, and I am sure you'll easily find it by doing a web search
on it).
The third way of addressing 5.1 surround in windows is to get something
like softencode (and dish out major $) which can supposedly do that kind
of encoding, or the pan-something plugin for cooledit pro, since, as far
as I understand the issue, the surround stuff can be easily embedded
into the regular stereo wav file, so it in reality is not so easily
separable (other than using EMU APS drivers).
Hope this helps!
Ivica Bukvic
-----Original Message-----
From: owner-linux-audio-dev_AT_music.columbia.edu
[mailto:owner-linux-audio-dev_AT_music.columbia.edu] On Behalf Of STEFFL,
ERIK *Internet* (SBCSI)
Sent: Wednesday, November 21, 2001 4:04 PM
To: 'linux-audio-dev_AT_music.columbia.edu'
Subject: RE: [linux-audio-dev] suggestion for developers: "real"
quad-channel output on an SBlive
> -----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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