[alsa-devel] Enabling in-kernel synch for M-Audio boards

John Rigg aldev at sound-man.co.uk
Tue Sep 18 08:57:23 CEST 2007


On Mon, Sep 17, 2007 at 08:44:03PM +0100, John Rigg wrote:
> On Mon, Sep 17, 2007 at 12:22:19PM +0200, Ludovico Verducci wrote:
> > Hello all! 
> >  
> > I'm developing a complex multichannel audio distribution system where 
> > multiple linux boxes will stream audio data over ethernet and then 
> > should play audio at sample level resolution synchronization. The boxes 
> > clocks are synchronized over ethernet using PTP. 
> > I need to keep in synch the audio board's clocks and I can't use an 
> > external wordclock nor s/pdif. 
> 
> Won't this cause serious clock jitter problems? I don't see how the
> PCI bus can deliver precise enough timing, considering how much other
> data it has to handle.

And I can't see any way that the clocks can be synced to sample
accuracy over ethernet. That's what external word clocks are for.
Even with a word clock I suspect that the latency of the
ethernet connection would be too high to allow sample accurate sync
of the audio.

John


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