Re: dtas-player warning

[Eric Wong]

Rene Maurer <address@hidden> wrote:
> Hello
> 
> First of all: dtas is great!

Thanks!

> When playing flac file over USB, dtas-player displays the following
> warning:
> 
> play WARN alsa: can't encode 32-bit Signed Integer PCM

Yes, I get this too.  This is because dtas (and sox) operates at 32-bit
internally and most soundcards cannot play at 32-bit.
32-bit is good for applying effects, but it requires sox to convert
back to 24 or 16-bit for playback.

> I have done the following to enable my USB-DAC:
> dtas-ctl sink ed default env.AUDIODEV=hw:1,0 env.AUDIODRIVER=alsa
> 
> When I do in a shell:
>     export AUDIODRIVER=alsa
>     export AUDIODEV=hw:1,0
>     play x.flac

This was a 16-bit FLAC file, I suppose?

> .... no warning is displayed.
> 
> I am using dtas 0.5.0.
> 
> Any suggestions?

I suggest just ignoring the warning.  You should not get any quality
loss if you run w/o effects (this includes software volume/ReplayGain).

If you do run effects, perhaps adding "dither -s" for 16-bit will improve
quality[1]. No dithering is needed for 24-bit DACs, AFAIK.

You can also try (not suggested, though):

        dtas-ctl format type=s16

This is not suggested if you use any effects at all, especially
software volume/ReplayGain.  You can see the effects chain more
clearly if you set SOX_OPTS=-V3 (or any higher number)

There's also some 32-bit USB DACs on the market nowadays, but I don't
think theres any real-world difference from 24-bit DACs.

[1] - I've personally not heard the difference between dither types,
      but the sox documentation seeems to recommend "dither -s" for
      16-bit, and sox touts it's dither implementation on the website.