From: Alfs Kurmis <kallipygos@...>

To: <linux-audio-dev@...>

Subject: Re: [LAD] FFT 1D real

Date: Monday, March 14, 2011 - 7:50 pm

What is good/best way to calculate values for visual 10-20 hopping---moq13001322345b4c02632d87968dbbf67d7f3fdb7c1c

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Content-Transfer-Encoding: quoted-printableCit=C4=93jot *Fons Adriaensen [1]*:

bars like in GUI audio players ?

Can U gimme pointers to such functions ?

What about all Radix algorithms ?

Tnx in advance

Alf

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Cit=C4=93jot **Fons Adriaensen <fons@linuxaudio.org>**: > How from ...1024 or 2048 or 4096... FFT return values i =

calculate > power magnitudes for all bands, > and fin=

ally values for visual 10-20 hopping bars, like in Winamp , > XM=

MS , QMMP ... ? If you want such a display the FFT is not =

a good way to do it. It's possible but not simple if you want a cor=

rect result. What is good/best way to calculate v=

alues for visual 10-20 hopping bars like in GUI audio players ? > 43303.2715 + 796.7285 =

=3D 44100 or 44100 - 43303.2715 =3D 796.7285> > Why Frequency=

796.7285 is mirrored as Frequency 43303.2715 , and magnitude for both Freq=

uencies is divided by 2 ???? Because you are using a compl=

ex FFT, and the imaginary part of your signal is zero. That means t=

hat the spectrum must be symmetric. > Is here w=

ay direct calculate full magnitude and without Frequency > mirro=

ring , in band 0 Hz ... FSampl/2 ONLY , Use an FFT operati=

ng on real data instead of complex. Can U gimme pointer=

s to such functions ?What about all Radix algorithms ? <=

br /> Tnx in advance Alf ---------- P=C4=81rs=C5=ABt=C4=ABt=C4=81s =

v=C4=93stules beigas ----------

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Re: [LAD] FFT 1D real, Alfs Kurmis, (Mon Mar 14, 7:50 pm)

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