From alsa-devel-owner@alsa.jcu.cz  Tue Jan 19 12:06:59 1999
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Date: Tue, 19 Jan 1999 12:06:02 +0100 (CET)
From: Jaroslav Kysela <perex@jcu.cz>
To: Guenter Geiger <guenter.geiger@psp-vie.be.philips.com>
cc: alsa-devel@alsa.jcu.cz
Subject: RE: hi-res pcm sound support
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On Tue, 19 Jan 1999, Guenter Geiger wrote:

> > -----Original Message-----
> > From: Jaroslav Kysela [mailto:perex@jcu.cz]
> >
> > Note that any conversion si time consuming... I think that
> > the best way is
> > transfer data to hardware unchanged if possible.
> >
> > 24-bit and 32-bit samples should be probably ok? I really
> > don't know which
> > data are expected from DSPs or CODECs which supports 16+-bit
> > resolution..
> >
> 
> My experience is that most of the DSPs will transfer data in double word format
> and cut
> the least significant 8 bits. (e.g Turtle Beachs Multisound). So you dont have
> to do conversion.
> 
> The second point is, that really nobody wants to use a 24 bit format on the
> application side,
> so providing 32 bit formats will be enough.

Yep, fine, are these definitions enough?

#define SND_PCM_SFMT_S32_LE             11
#define SND_PCM_SFMT_S32_BE             12
#define SND_PCM_SFMT_U32_LE             13
#define SND_PCM_SFMT_U32_BE             14

#define SND_PCM_FMT_S32_LE              (1 << SND_PCM_SFMT_S32_LE)
#define SND_PCM_FMT_S32_BE              (1 << SND_PCM_SFMT_S32_BE)
#define SND_PCM_FMT_U32_LE              (1 << SND_PCM_SFMT_U32_LE)
#define SND_PCM_FMT_U32_BE              (1 << SND_PCM_SFMT_U32_BE)

							Jaroslav

-----
Jaroslav Kysela <perex@jcu.cz>
Academic Computer Centre, University of South Bohemia
Branisovska 31, C. Budejovice, CZ-370 05 Czech Republic


