[alsa-devel] trace PCM data from usb bus to alsa lib
tiwai at suse.de
Wed Jun 17 10:18:02 CEST 2009
At Wed, 17 Jun 2009 16:10:26 +0800,
Zero Luo wrote:
> Dear Takashi,
> Data from usb dongle is 16K*16 bit PCM data.
And what is the format and channels you are using in alsa-lib?
alsa-lib itself can convert formats and channels automatically if needed.
> 2009/6/17, Takashi Iwai <tiwai at suse.de>:
> At Wed, 17 Jun 2009 07:25:25 +0000 (UTC),
> ZeroCluo wrote:
> > Hi
> > I am trying to trace the Audio data from usb bus.
> > in kernel:
> > dump data in retire_capture_urb() ,found data format is like:
> > AABB 0000 CCDD 0000 ;
> > but in alsa library ,
> > dump data in snd_pcm_mmap_begin(),the "0000" is cut,only "AABB CCDD",
> > Do you know when and where those "0000" is cut?
> Are you using the native format that the hardware runs?
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