[alsa-devel] RFC: support for 12 & 24Khz

[Takashi Iwai]

At Thu, 25 Jul 2013 21:15:01 +0530,
Vinod Koul wrote:
> 
> On Thu, Jul 25, 2013 at 08:50:40AM +0200, Clemens Ladisch wrote:
> > Vinod Koul wrote:
> > > For compressed audio we also need to support the PCM rates of 12 and 24KHz.
> > >
> > > Looking at pcm.h these are not defined
> > 
> > You don't need such symbols to use a rate.  These symbols are intended
> > for often-used rates.  As long as only one or two drivers use a rate,
> > they can just set KNOT and install a constraint.
> okay so how exactly is the rate passed to driver and converted and sent to
> drivers?

Define the own hw_constraint.  Usually it's implemented via
snd_pcm_hw_constraint_list().

> > > But am worried about wider impact of adding these rates.
> > >
> > > Can you let me know if more is required to be done or below is fine
> > 
> > Grep for 176400 in sound/core/, include/, and in alsa-lib.
> SNDRV_PCM_RATE_176400?

Heh, this was an already added one.  Rather take a look at
SNDRV_PCM_RATE_KNOT.


Takashi