Re: multi-mono-channel sound card Ruslan Bukin Fri Feb 03 02:01:59 2012
Hi, On Sat, Jan 21, 2012 at 05:46:16PM +0200, Alexander Motin wrote: > On 01/21/12 16:12, Ruslan Bukin wrote: > >My multichannel sound card (RME HDSPe AIO) is support > >SND_FORMAT(AFMT_S32_LE, 1, 0) only. > > > >I call pcm_addchan(..), which triggers chan_init(..,*snd_dbuf,..) > >Addr of snd_dbuf I write to card in slot N. > >In result I have /dev/dsp0.pN devices (one device per each mono channel) > > > >Works perfectly, sounds great, but in mono mode. > > > >I'm interested, what is the right way to implement > >stereo pair of channels per one device file like in OSS? > > pcm_addchan() registers set of equal playback/record channels that > are supposed to be mixed into the same signal. It is hardware > equivalent of vchans. It has nothing common with multiple speakers. > > Multichannel audio is always multiplexed and AFAIk there is no > demultiplexing in sound(4). Sound(4) can upmix/downmix channels, > change their order, format, rate, but not demultiplex. > > I see only two ways: > - implement demultiplexing in driver -- that is not easy, but I > believe it should be possible; > - export each input/output connector as separate PCM device and let > some user level software to do demultiplexing -- that is easy and > that is what snd_emu10kx does. snd_emu10kx(4) recommends to use > pulseaudio for demultiplexing. Thanks. I have implemented demultiplexing. Works great. I will release the driver soon. -Ruslan > > -- > Alexander Motin _______________________________________________ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-multimedia To unsubscribe, send any mail to "[EMAIL PROTECTED]"