On Sat, Dec 18, 2010 at 03:19:14PM +0100, Jörn Nettingsmeier wrote: > On 12/16/2010 08:49 PM, Lee Azzarello wrote: > > On Thu, Dec 16, 2010 at 1:36 PM, Lee Azzarello <l...@rockingtiger.com> > > wrote: > >> On Thu, Dec 16, 2010 at 6:58 AM, torbenh <torb...@gmx.de> wrote: > >>> On Thu, Dec 16, 2010 at 08:02:29AM +0100, Luis Garrido wrote: > >>>> On Thu, Dec 16, 2010 at 4:21 AM, Lee Azzarello <l...@rockingtiger.com> > >>>> wrote: > >>>>> Hello, I'm looking for some advice for an interesting symptom of > >>>>> putting my M-Audio Fast Track Pro USB sound card into ALSA multi mode. > >>>> > >>>> I have no idea what might be happening, but an alternative to use > >>>> several alsa devices in jack would be the alsa_in and alsa_out > >>>> utilities shipped with jack, perhaps that will give you less trouble? > >>> > >>> hmm... the interesting thing is that he actually claims to not have > >>> trouble. he only gets xrun callbacks. this is weird. > >> > >> > >> I'll test the alsa_(in|out) utilities later today. > > > > Great success! alsa_out on the second device exposes those two > > additional channels to JACK and I can connect any application to them > > without jackd printing messages about xrun callbacks. > > torben, i wonder: will alsa_[in|out] be perfectly bit-transparent when > the two interfaces it bridges are externally synced, or will its > tracking algorithm keep oscillating around the correct samplerate?
it will oscilate, but the oscilation will get slower and slower, and its about 0.00001% so this is going to be pretty good. but its not perfect. there are a bit of scheduler uncerteinties, which might perturbate the timebase. if your interfaces are synced just use the pcm multi approach. if you dont care for bit-transparency, and dont want to edit a config file, use alsa_io. the main purpose of alsa_io is jackd running with a jittery timebase. and i prefer optimizing it at that end. > > _______________________________________________ > Linux-audio-dev mailing list > Linux-audio-dev@lists.linuxaudio.org > http://lists.linuxaudio.org/listinfo/linux-audio-dev -- torben Hohn _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-dev