uaudio - distorted output

[Alexander Leidinger]

Hi,

attached are the config descriptors and the device dump of two uaudio  
devices. Both exhibit distorted audio output. It sounds a little bit  
like clipping / not feeding enough samples fast enough...

I played around with dev.pcm.2.bitperfect=1, dev.pcm.2.play.vchans=0,  
dev.pcm.2.play.vchanrate and hw.snd.latency=1...10.

At some point vchanrate doesn't work anymore, it always stays at 4.0  
audio, even when trying to go back to 2.0. I have to usbconfig reset  
the device.

Sometimes (rarely) when playing around I get clear audio output, but  
when I try to reproduce it (going back to default value for the last  
sysctl setting and then going back again to the same setting again),  
the audio is distorted again.

To me it sounds like some kind of buffer is not big enough or the data  
is not delivered fast enough to the uaudio device. But this is a  
dual-socket system with:
     CPU: Intel(R) Xeon(R) CPU           E5620  @ 2.40GHz (2133.36-MHz  
K8-class CPU)
     FreeBSD/SMP: Multiprocessor System Detected: 16 CPUs
     FreeBSD/SMP: 2 package(s) x 4 core(s) x 2 hardware threads
And while playing around with uaudio the system has a load of around  
1, so I would expect CPU/RAM is not an issue here.

I would expect that just attaching an uaudio device like those and  
using madplay/mpg123 would just work (not looking at digital output  
and 5.1/7.1 output for video, just the basics like stereo output of  
MP3). So either I do something fundamentally wrong and would need a  
hint with the cluebat, or I would need some description how to debug  
this further from the USB side...

Bye,
Alexander.

-- 
http://www.Leidinger.net Alexander at Leidinger.net: PGP 0x8F31830F9F2772BF
http://www.FreeBSD.org    netchild at FreeBSD.org  : PGP 0x8F31830F9F2772BF
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