[linux-audio-dev] mux concept paper
S.W.Harris at ecs.soton.ac.uk
Thu Feb 17 14:29:01 UTC 2005
On Thu, Feb 17, 2005 at 02:00:24 +0000, mimo wrote:
> Paul Davis wrote:
> >>complaining. But my experiences with jack are negative. First time I
> >>started looking at it I had huge expectations after all that I had read.
> >> First problems, after a couple of second of running without any
> >>actual processing going on, strange noise artefacts kind of getting
> >>worse. I had a look at source code and realise that it bases its time
> >>calculation on cpu MHz in /proc/cpuinfo. I dont know about your machine,
> >>but on my machine(s) a) this is a float and b) it's slightly different
> >>every time I boot the machine.
> >this has nothing to do with your noise. JACK uses CPU Hz to provide a
> >UST value. i am puzzled by the fact you are the 2nd person to think
> >that JACK's timing is somehow based on system timers and so
> >forth. JACK (in regular mode, using one of the normal backends) is
> >driven 100% by the interrupt from your audio interface. whether or not
> >the CPU Hz value is correct has (effectively) zero impact on audio
> >generation and timing.
> Just out of interest, if it is dependent on the audio hardware, why do I
> get the same problems with different sounds cards on the same machine,
> and a colleague gets them with completely different hardware all the
> same. Any ideas what might be the reason? Anyone else with the same
Are you running it in realtime mode? If not, and jackd misses realtime
deadlines you will often get noises in the output.
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