Re: [Alsa-user] Trying to get arecord/aplay to work with M-Audio

[Takashi I. <ti...@su...>]

At Fri, 25 Apr 2008 20:45:03 +0300,
Sergei Steshenko wrote:
> 
> On Fri, 25 Apr 2008 16:23:06 +0200
> Takashi Iwai <ti...@su...> wrote:
> 
> > At Fri, 25 Apr 2008 16:19:38 +0200,
> > I wrote:
> > > 
> > > At Thu, 27 Mar 2008 01:58:50 +0100,
> > > Rene Herman wrote:
> > > > 
> > > > On 26-03-08 23:57, Bill Unruh wrote:
> > > > 
> > > > > On Wed, 26 Mar 2008, Helge Fredriksen wrote:
> > > > > 
> > > > >> Ok, here's what I found out:
> > > > >>
> > > > >> Since these cards seem to lack the support for doing frequency conversion in
> > > > >> HW, you simply need to use the alsa plugin
> > > > >> plughw instead of hw when referring to the card:
> > > > >>
> > > > >> arecord -Dplughw:0  test.wav
> > > > >> aplay -Dplughw:0 test.wav
> > > > > 
> > > > > AFAIK, alsa frequency conversion is pretty primative ( linear
> > > > > interpolation) which produces a huge amount of noise/distortion.
> > > > 
> > > > The default is, but if you install the alsa-plugins package (and 
> > > > libsamplerate) and add a line
> > > > 
> > > > defaults.pcm.rate_converter "samplerate"
> > > 
> > > Or "speexrate".  This is usually much faster.
> > 
> > And forgot to write: you don't have to add anything to asoundrc for
> > speexrate plugin.  Install it, then alsa-lib will pick it up
> > automatically.
> > 
> > 
> > Takashi
> > 
> 
> After some web search I see that there are several quality settings for
> "speexrate".
> 
> How does one choose/change the quality settings ?

Use "speexrate_best" instead of "speexrate", for example.
See alsa-plugins/doc/speexrate.txt for details.


Takashi