[alsa-devel] trace PCM data from usb bus to alsa lib

[Takashi Iwai]

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.


Takashi

> 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?
> 
>     Takashi
> 
>