[alsa-devel] SNDRV_PCM_FMTBIT_S24_LE vs. SNDRV_PCM_FMTBIT_S24_3LE

[Clemens Ladisch]

dustin at seznam.cz wrote:
> >  What is the difference between SNDRV_PCM_FMTBIT_S24_LE and
> >  SNDRV_PCM_FMTBIT_S24_3LE?
> 
> The asound.h says S24_LE is stored in lower three bytes of four, whereas
> S24_3LE is stored in three bytes total.

To use a sample format with 24 bits stored in the upper three bytes of
four, use S32_LE.  In that case, you have to call
"snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24)" in the PCM open
callback to tell ALSA that some of the lower bits aren't used.


HTH
Clemens