[linux-audio-dev] mux concept paper

mimo mimo at restoel.net
Thu Feb 17 14:45:22 UTC 2005


Steve Harris wrote:
> 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 
>>experiences?
> 
> 
> Are you running it in realtime mode? If not, and jackd misses realtime
> deadlines you will often get noises in the output.

Yes, and root, tried evryting I could think of. And again, this happens 
without any load.

mimo

> 
> - Steve


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