Date: Thu, 4 Apr 2002 14:49:37 -0500 From: The Anarcat <anarcat@anarcat.dyndns.org> To: Lars Eggert <larse@ISI.EDU> Cc: John Utz <john@utzweb.net>, multimedia@FreeBSD.ORG Subject: Re: Soundblaster Live rear channels? Message-ID: <20020404194937.GE279@lenny.anarcat.dyndns.org> In-Reply-To: <3CACAC92.3040506@isi.edu> References: <3CAC8E70.3040700@isi.edu> <Pine.LNX.4.44.0204041147440.2292-100000@jupiter.linuxengine.net> <20020404193214.GD279@lenny.anarcat.dyndns.org> <3CACAC92.3040506@isi.edu>
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[-- Attachment #1 --] On Thu Apr 04, 2002 at 11:42:10AM -0800, Lars Eggert wrote: > The Anarcat wrote: > >FreeBSD Audio Driver (newpcm) Mar 27 2002 12:56:06 > >Installed devices: > >pcm0: <Creative EMU10K1> at io 0x9000 irq 5 (4p/1r/0v channels duplex) > > > >So it has 4 play channels. newpcm supports multiple through the use of > >multiple channels, AFAIK. On -stable, newpcm supports this through > >hw.snd.pcm0.vchans. The default value is 0 which means there is only > >one virtual channel available. If you bump this to 1 or 2, you have > >more virtual channels available. These are accessible through > >/dev/dspX.Y where Y is the virtual channel. > > I think I was unclear here when using "channel". Yes. > What I'm trying to do > is getting sound out of the two rear speakers with a 5-speaker setup. > There's two separate cables that go from the soundcard to the speakers, > one is for the front pair and subwoofer, the other drives the two rear > speakers. No signal comes out of the latter. > > My understanding was that "virtual" channels act like virtual sound > cards, i.e. each applications gets what looks like a separate sound > device, and the kernel muxes the output. I'm not sure this has anything > to do with the mixer channels, which is where I would expect the rear > channel to show up. And this is why I brought up the "mapping" issue. I think pcm can use the multiple channels available (front and rear) through the virtual channels technique. The kernel can mux the input from various apps into a single sound channel, so it's likely that it can do the opposite: mux a single sound input to multiple channels. I can't answer wether it is the case, but it's likely to be. Cameron Grant <gandalf@vilnya.demon.co.uk> would be the one to answer that, I think. A. [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (FreeBSD) Comment: For info see http://www.gnupg.org iEYEARECAAYFAjysrlEACgkQttcWHAnWiGdVRgCbBoPDUX+4oxhPgCuMcbn0QD6o g9EAoIYWQu7BB51V2cyeBw0HLaOpdesv =Pq2n -----END PGP SIGNATURE-----help
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