On Thu, Nov 26, 2009 at 08:55:50AM +0000, Folderol wrote: > On Thu, 26 Nov 2009 06:36:07 +0100 > torbenh <torb...@gmx.de> wrote: > > > On Tue, Nov 24, 2009 at 08:34:53PM +0100, Karl Hammar wrote: > > > Florian Faber: > > > > Karl Hammar wrote: > > > > > [..ethernet transports..] > > > > > And we are missing an open protocol for this. > > > > What is wrong with netjack? It's made for point-to-point and very > > > > simple. You just have to solve the clock issue unless you want to lose > > > > bit transparency. > > > > > > Ohh, sorry, I got the impression it was not ready. I don't mind being > > > wrong in that. > > > > may i kindly ask what gave you that impression ? > > i admit that some jack versions in svn were broken for the LAN use-case > > because i am focussing on making it work for wireless and > > transcontinental internet connections. > > I'm not sure why, but I had an impression of 'unreadiness' too :o
:S great. did you try it, and it didnt work ? > > > but the lan use-case it pretty trivial and doesnt need all this deadline > > machinery. > > > > if you just want to build a network soundcard, and use jack on a > > computer with that, its ready for 3 years now !!! > > The remaining issue then is how much additional latency does netjack > introduce? I think, eventually, this will turn out to be the most > critical issue. if you dont saturate the link, its one period. you have the same problem with usb soundcards. for 100Mbit the threshold where you need 2 periods, is somewhere around 12 channels. > > > having more than one network soundcard, and keeping stuff in sync is > > more tricky. it requires that you can control the wordclock on that > > soundcard, and you need a special version of alsa_out.c > > which instead of resampling controls the wordclock frequency. > > If there is no internal sound card, why is there any need for alsa? > > Wordlock may not be as difficult as it first seems. A bit I originally > wrote to LAU... if you have a master clock, and want to adjust your output to this, then the alsa_out program would be what you want. it extracts the clock driving jackd, and is able to control a resampling rate so that the phase is pretty constant. > > > Looking up the AES spec quickly reveals 48kHz +/- 10ppm. If the > > card's master oscillator has that kind of stability, it would surely > > require only very tiny slow adjustments to keep two of them in sync. > > Worst case would be them consistently drifting the maximum allowance in > > opposite directions, which if my maths is up to scratch results in > > about a second before they would actually get out of step by 1 cycle. > > > > A quick google reveals 5ppm temp compensated oscillators with a a 7ppm > > voltage controlled pull-in - no idea how much these cost though. > > Even without this, I wonder what the audible effect on real music would > be of just dropping one sample per second. It might be worth doing some > experiments to find out. i dont understand why you want that... > It also occurs to me that although we want to lock frequency, phase > relationship between cards is a red herring. Signals from different > sources will not have any phase relationship, so why should the cards? alsa_out is able to deliver that. > > -- > Will J Godfrey > http://www.musically.me.uk > Say you have a poem and I have a tune. > Exchange them and we can both have a poem, a tune, and a song. > _______________________________________________ > Linux-audio-dev mailing list > Linux-audio-dev@lists.linuxaudio.org > http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev -- torben Hohn http://galan.sourceforge.net -- The graphical Audio language _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev