Re: USB-audio strange problems

[Pavel Machek]

> At Wed, 19 Mar 2008 22:12:47 +0100,
> Pavel Machek wrote:
> > 
> > Hi!
> > 
> > Ok, so it took me a year to get back to this bug. Oops.
> 
> Oh well, I don't remember what was the exactly problem...

Yes, sorry about that.

> > > Yep, let's fix it.  Just to make sure (ane debugging easy atm), could
> > > you attach the following?
> > > 
> > > - content of /proc/asound/cards
> > > - content of /proc/asound/card*/stream*
> > > - the output of "lsusb -v"
> > > - the generated file via "alsactl -f store somefile"
> > > 
> > > If I remember correctly, alsamixer at least doesn't break if you build
> > > snd-usb-audio driver with IGNORE_CTL_ERR enabled, right?
> > 
> > I got the usb soundcard to work. I still have IGNORE_CTL_ERR enabled.
> > 
> > Problem was not mixer after all... somehow it expects me to play sound
> > as 8-bit, and then I can play 16-bit mono and actually hear
> > it. _Strange_.
> > 
> > So:
> > 
> > mplayer -ao alsa:device=hw=0 -af format=u8  KDE_Startup.wav
> > mplayer -ao alsa:device=hw=0 -af format=s16le -af resample=48000  -af channels=1 KDE_Logout_1.ogg
> > 
> > ...plays both files. 
> > 
> > Forget about the first mplayer, and it will play nothing.
> 
> Dalls DS4201 has a known bug that it doesn't handle U8 format but only
> S8 format.  The driver changes the supported format flags from U8 to
> S8 when this USB ID is detected.  So you cannot play U8 format
> natively.  (Still strange that it is accepted by mplayer.)

But problem is: I have to. Otherwise the second mplayer will produce
just silence.

Also, even with that treatment, I'm unable to play stereo :-(.

How to debug this?
									Pavel
-- 
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(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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