[alsa-devel] Delay calculations for USB audio?
Gabriel M. Beddingfield
gabrbedd at gmail.com
Fri Sep 28 13:23:14 CEST 2012
On 09/28/2012 06:00 AM, David Henningsson wrote:
> (Oh, and btw, if you have an idea of the crackling/distorted USB audio,
> let me know. I'm using a standard Logitech USB Headset, using
> speaker-test -c 2 -D plughw:Headset -t sine -r 48000
> I can make the problem go away using any of these options:
> * Booting a 3.2 kernel - I've tried 3.5, 3.6-rc7 and 3.2
> * Choosing the 44100 sample rate instead of the default of 48000
> * Selecting the outer USB port instead of the inner one. Yes, there
> are two USB ports next to each other, and this only happens on one of
> them. (!))
The last statement sounds like you're sharing a hub with another device
that has reserved bandwidth. For example, a USB webcam will often do
this. Audio will work for a while and then get pre-empted.
Use 'lsusb -t' to view your USB layout.
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