[PD] Re: [PD-dev] i need some help with this

marius schebella marius.schebella at chello.at
Wed Sep 4 08:45:46 CEST 2002

scotty, beam me up a little!
you can have the convolution process on two given audio wave-files, thats
one thing, but also on streaming data. and the fft-windows can be smaller
than the samples or bigger (twice as big, if you like.)
it is like a reverb: you can wait until the reverberation of a soundfile is
finished or just play and play...
the first method could make sense if you have very long and complex
wavefiles to have a clean special effect without any glitches or loops. the
problem with this method is the handling of large files and a lot of cpu is
needed. this cannot be done in realtime, because you only can listen to the
sound, if the calculation has finished, but of course it can be done in
with the other method you split the wave files in slices and convolute
always small parts. this is something different. after the convolution they
are put together again.
hmm, can you explain again, what you want to do, which sounds to use, ...?

----- Original Message -----
From: "J. Scott Hildebrand" <jshildebrand at ucdavis.edu>
To: <zmoelnig at iem.at>
Cc: "J. Scott Hildebrand" <jshildebrand at ucdavis.edu>; <pd-dev at iem.kug.ac.at>
Sent: Tuesday, September 03, 2002 9:08 PM
Subject: Re: [PD-dev] i need some help with this

>        i wouldn't mind at all to do the convolution with the built-in fft
> stuff. the only problem is that i don't quite understand how it works.
> what i need is to input x amount of samples, and get out y amount of
> output, which should be at least 1.5 times the original amount + padded
> zeros to equal 2 times the original amount. only then can i write an
> overlap and add method.
>                      scott
> On Sat, 31 Aug 2002 zmoelnig at iem.at wrote:
> > hi scott !
> >
> > i really recommend that you read the mail i send you when qou first
posted your
> > piece of code.
> > i really tried to point out all the faulty pieces of code (especially
> > neveroccuring reset of apple)
> > and i again give you one advice: add debugging code like "post()" to
show you
> > where the error occurs !
> >
> > i am not going to do the programming for you (and i hope no one else
will do)
> > - just read the mails. (it's all in there)
> >
> > and again:
> > is there any major reason not to do the convolution as an abstraction ?
> > to not use pd's built in fft-routines ?
> >
> >
> > mfg.cd.sar
> > IOhannes
> >
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