[alsa-devel] frequency analysis with alsa and fftw

Jan-Benedict Glaw jbglaw at lug-owl.de
Sun Dec 27 15:04:54 CET 2009

On Sun, 2009-12-27 14:50:20 +0100, Markus Vogl <markus.vogl at gmx.net> wrote:
> Von: Jan-Benedict Glaw [mailto:jbglaw at lug-owl.de]:
> > On Sun, 2009-12-27 13:26:31 +0100, Markus Vogl <markus.vogl at gmx.net> wrote:
> > > my project is to analyse the mic input frequency from my asus
> > > eepc 1008ha with ubuntu 9.10  and show it in a terminal window.
> > > i would use my acoustic 6 string guitar to play in front of my
> > > netbook.
> > >  
> > > i´ve testet the howto from linuxjornal.com ..
> > > http://www.linuxjournal.com/article/6735
> > >  
> > > ...but i´ve no plan to use the mic input and  then analyse it
> > > with fftw.
> > 
> > Why do you need to do ALSA programming in the first place? Isn't
> > it enough to use any given ALSA-capable audio recorder (eg.
> > arecord) to record some sound, convert it to raw PCM data (eg. cut
> > off the WAV header) and then shift all the data into the FFT lib?
> i have to do this in realtime (like a guitartuner) and with my
> "project" i have to see the frequency shift in realtime in a
> terminal window.

Sure. Just let eg. arecord write to stdout or to a FIFO and read the
data from there. You can directly request raw output, all you need to
do is to shouvle the data through the FTT lib...

PS: I did some clean-up of your TOFU email.

      Jan-Benedict Glaw      jbglaw at lug-owl.de              +49-172-7608481
Signature of:                     Eine Freie Meinung in einem Freien Kopf
the second  :                   für einen Freien Staat voll Freier Bürger.
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