Re: [Jack-Devel] extra latency compensation

Chris Caudle wrote:
> On Tue, April 19, 2011 1:05 am, Clemens Ladisch wrote:
> > In addition to the already mentioned USB queueing delay
> > (up to 24 ms, depending on the period size)
> 
> Is that constant?

Yes.

> If so, it should get calibrated out by using the jack_iodelay
> measurements, right?

Yes.

> > USB also adds a somewhat random delay
> > between the playback and capture streams.
> 
> Or is it +/-1ms worst case?

In practice, yes.

> > all these latencies can be explained by known deficiencies
> > in the Linux USB stack.
> 
> The general USB stack used by all applications, or specifically the USB
> audio device support?  Is the deficiency something that can be corrected
> in ALSA code, or would have to be addressed in the general USB support in
> the Linux kernel?

It would be possible to add some workarounds in the audio driver, but
doing this right in the USB stack would be easier.


Regards,
Clemens

1303281105.24412_0.ltw:2,a <4DAE7E23.7040000 at ladisch dot de>