[alsa-devel] Multiple channels mapping

Takashi Iwai tiwai at suse.de
Wed Feb 8 10:23:45 CET 2012


At Wed, 08 Feb 2012 10:18:29 +0100,
Clemens Ladisch wrote:
> 
> Takashi Iwai wrote:
> > Currently the channel-mapping information is a missing piece in ALSA
> > framework, and it's a very long-standing item on my TODO list.
> >
> > The implementation itself should be easy, but the only question is the
> > API design.  If you have a good proposal, please speak up.
> 
> TLVs on media controller entities.

Well, my concern is that it might be too far from the other PCM
stuff.  How the implementation would look like?

BTW, the channel-mapping info can be useful for the automatic plug
layer, too.  It would re-route the channels when not following
ALSA-standard maps automatically, for example.  (Remember some old
AC97 chips.)

More question is whether this information should be available before
or after hw_params setup.


thanks,

Takashi


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