Re: new pcm format(s)

[Takashi Iwai <tiwai@suse.de>]

At Thu, 22 Aug 2002 07:37:42 -0700 (PDT),
Guilhem Tardy wrote:
> 
> > > Anyway, I found out that there's not so much space left for more formats.
> > 
> > the space must be enough.  at the last change of hw_params struct, we
> > extended the space for the sample format.
> 
> Indeed, I managed to build RC3 at last (I'll port all my stuff to RC3 over the
> WE) and found out that the SNDRV_PCM_FMTBIT_ are now defined as 64-bit unsigned
> integers. But I think it would be worthwhile in the long run to use subformats.

it's only on the kernel side for ease of use.
the api itself allows up to 256 (or more) formats.
so we can change it at any time.

> 
> > > Therefore, I added one for G726 and started adding subformats (a field that
> > > was unused until now). This also means that I need to update the function
> > > snd_pcm_format_width() in order to deal with subformats.
> > 
> > yes.
> > if you finished, please send the patch.
> > the patch is always welcome.
> 
> I built the ALSA framework (RC2) with those changes, but then all drivers must
> be updated (e.g. dummy.c at line 207) to call snd_pcm_format_width() with 2
> parameters: the format AND the subformat. Is this something you think would be
> possible?

is it needed to be a subformat?

also, note that runtime->format is not a mask but a value.
hence you can combine the format and subformat in each 16bit if
necessary.


Takashi


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