low latency USB audio broken? [was Re: [linux-audio-user] open source firewire]

Ryan Gallagher ruinaudio at comcast.net
Sun Nov 28 18:49:30 EST 2004


On Sun, 2004-11-28 at 18:34 -0500, Lee Revell wrote:
> On Sun, 2004-11-28 at 17:17 -0600, Ryan Gallagher wrote:
> > On Sun, 2004-11-28 at 15:51 -0500, Lee Revell wrote:
> > > On Sun, 2004-11-28 at 15:35 -0500, Lee Revell wrote:
> > > > Can you provide more information?  What exactly doesn't work?  What are
> > > > the symptoms?
> > > 
> > > OK I updated the JACK bug report.  Can you (or any USB audio users)
> > > repeat the test with the latest JACK and ALSA versions (preferably from
> > > CVS), with both alsaplayer and jackd, at 44100 and 48000Hz?  Also please
> > > try the JACK test in full duplex, capture only, and playback only mode.
> > 
> > Sure, glad to (though I'm not set up to do capture only).  Thanks for
> > taking an interest.
> > 
> > The results with CVS jackd and (very recent alsa 1.0.7) on a 2.6.8.1
> > kernel with volluntary-preempt are... the same as a year ago.
> 
> You can do capture only like:
> 
>    jackd -d alsa -C hw:1 ...
> 
> and playback only with:
> 
>    jackd -d alsa -P hw:1 ...
> 
> How does this sound?  It's possible that capture and playback interfere
> with each other.

Yeah, I know how to do playback only (thanks - see the tests for results
of -P).  The emi 2|6 has no mic pres and I don't have a line level
source to feed it atm so I can't do capture only tests... as of now I
havent gotten it to actually capture anything, that'll be the next round
of testing.

I'm also playing around with -n with some preliminarily good results...
I'll post a followup in a while.

-ry

-- 
Ryan Gallagher <ruinaudio at comcast.net>




More information about the Linux-audio-user mailing list