[LAU] I just don't know Jack anymore.

Philipp Überbacher hollunder at lavabit.com
Thu Jun 3 20:48:22 UTC 2010


Excerpts from fons's message of 2010-06-03 23:02:46 +0200:
> On Thu, Jun 03, 2010 at 01:58:49PM -0700, Ken Restivo wrote:
> 
> > What is synchronous mode? (A link to the place in the docs would be a plenty good answer, sorry, I don't feel like fishing around in it right now).
> 
> AFAIK, synchronous mode is what jack1 does:
> 
>   read from soundcard
>   process graph
>   write to soundcard
> 
> while jack2's default mode is
> 
>   write output of previous cycle to soundcard
>   read from soundcard
>   process graph
> 
> which is somewhat more resilient to occasional xruns,
> but adds one cycle of latency.
> 
> Ciao,

According to http://www.grame.fr/~letz/Timing.pdf asynchronous mode is
only sensible to use when your audio cards driver interrupt is regular.
It also more or less explains how this can be measured.

I'm not totally sure how to interpret it properly in my case, but it's
a USB audio interface, which might be problematic by definition.
http://murks.lima-city.de/serendipity/uploads/timing1.png
In a sense it's regular... +/- 500usec all the way...

Well, smp doesn't make sense on my machine anyway, so I stick with jack1
(well, tschack atm.).
-- 
Regards,
Philipp

--
"Wir stehen selbst enttäuscht und sehn betroffen / Den Vorhang zu und alle Fragen offen." Bertolt Brecht, Der gute Mensch von Sezuan



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