yes, you are (unless you are using the sliding version or doing
additive synthesis). In a simple
explanation, that is because each bin has a limit to what frequencies
it can represent (a range), if you go above or below it, you will
'wrap-around'.

However, that is only the case for overlap-add IDFT-type resynthesis.
With additive synthesis in theory you can do whatever you want w
with the frequencies, since you are driving a bank of oscillators.

Victor

----- Original Message ----- 
From: "peiman khosravi" 
To: 
Sent: Thursday, March 05, 2009 10:07 AM
Subject: [Csnd] Re: Re: pvs and spectral warping (as in GRM tools)


Hi Victor and all,

Am I right to think that if you read the pvs signal into tables and
then simply multiplied the freq table values with a constant you
wouldn't end up with a transposer? But why is this the case?

Thanks in advance
Peiman

2009/3/4 peiman khosravi :
> Hello,
>
> Using vcopy and pvsftw I managed it. Thanks to studying the UDO by
> Matt Ingalls implementing spectral stretch. I have used his UDO as a
> starting point and change the core of it to enable warping. I have
> also changed the instrument to take stereo signal.
>
> Using csound~ maxmsp external I am now able to change the warping
> table in real-time.
>
> I have attached the UDO + a csd file demonstrating it's use. Please
> feel free to let me know if it works and what you think about it.
>
> Best
> Peiman
>
>
> 
> 
> 
> 
>
> sr=44100
> ksmps=10
> nchnls=2
>
>
>
> opcode warp,0,iiiiii
>
>
> inumbins, iampin, iampout, ifreqin, ifreqout, iwarp xin
>
> ; make sure we start with an empty table
> iclear ftgen 0, 0, inumbins, 2, 0
> tablecopy iampout, iclear
> tablecopy ifreqout, iclear
>
>
>
> kindex = 0
>
> loop:
>
>
> kind2 table kindex, iwarp
>
> vcopy iampout, iampin, 1, kindex,kindex
> vcopy ifreqout, ifreqin, 1, kindex, kindex
>
> vcopy iampout, iampin, 1, kindex,kind2
> vcopy iampout, iampin, 1, kind2,kindex
>
> vcopy ifreqout, ifreqin, 1, kindex, kind2
> vcopy ifreqout, ifreqin, 1, kind2, kindex
>
> kindex = kindex + 1
>
> if (kindex < inumbins) kgoto loop
>
> endop
>
> instr 1
>
> ;midi control
> kdry invalue "dry"
> kdry port kdry, 0.01
>
> kwet invalue "wet"
> kwet port kwet, 0.01
> ;;;;;;;;;;;;;;;;
>
> ain1, ain2 ins ;;;input, can be changed with a soundfile
>
> ; get input and do pvanal
> ifftsize = p4
> iol = p5
> iNumBins = ifftsize/2 + 1
>
>
>
> fsigl pvsanal ain1, ifftsize, ifftsize/iol, ifftsize*4, 1
> fsig2 pvsanal ain2, ifftsize, ifftsize/iol, ifftsize*4, 1
> ; [ or alternatively use pvsfread with a pvoc-ex file here ]
> fsig3 pvsanal ain1, ifftsize, ifftsize/iol, ifftsize*4, 1
> fsig4 pvsanal ain2, ifftsize, ifftsize/iol, ifftsize*4, 1
>
> iwarp ftgen 0,0,iNumBins,-7,0,iNumBins, iNumBins ;warping table UNTOUCHED
> ;this should be modified for warping effects
>
> iampin ftgen 0,0,iNumBins,2,0
> iampout ftgen 0,0,iNumBins,2,0
> ifreqin ftgen 0,0,iNumBins,2,0
> ifreqout ftgen 0,0,iNumBins,2,0
>
> iampin2 ftgen 0,0,iNumBins,2,0
> iampout2 ftgen 0,0,iNumBins,2,0
> ifreqin2 ftgen 0,0,iNumBins,2,0
> ifreqout2 ftgen 0,0,iNumBins,2,0
>
> ; export fsig to tables
> kflag pvsftw fsigl, iampin, ifreqin
> if (kflag > 0) then ; only proc when frame is ready
>
> ;warp
> warp iNumBins, iampin, iampout, ifreqin, ifreqout, iwarp
>
> ; read modified data back to fsrc
> pvsftr fsigl, iampout, ifreqout
>
> endif
>
>
> ; export fsig to tables
> kflag2 pvsftw fsig2, iampin2, ifreqin2
> if (kflag2 > 0) then ; only proc when frame is ready
>
> ; warp
> warp iNumBins, iampin2, iampout2, ifreqin2, ifreqout2, iwarp
>
> ; read modified data back to fsrc
> pvsftr fsig2, iampout2, ifreqout2
>
> endif
>
> ; resynthesize and output - compare with untouched right channel
>
>
> aout1 pvsynth fsigl
> aout2 pvsynth fsig2
>
> aout3 pvsynth fsig3
> aout4 pvsynth fsig4
>
> outs (aout1*kwet)+(aout3*kdry), (aout2*kwet)+(aout4*kdry)
>
> endin
>
>
>
>
> 
> 
>
> f0 86400
>
> i2 0 -1 2048 8
>
> e
>
> 
> 
>
>
>
>
>
>
> 2009/3/4 David Mooney/Maxine Heller :
>> Similarly, I've attempted to use vpvoc and tableseg for spectral warping
>> operations, but this does not seem to work (using the example in the 
>> Csound
>> Book as a test using a file created with pvanal. The file works fine with
>> pvoc). Before spending more time on this, am I recalling correctly that
>> there is some problem with vpvoc in 5.x? Is there something else Peiman 
>> and
>> I should be using?
>>
>> Thanks--
>>
>> --David
>>
>> At 09:15 AM 3/2/2009, you wrote:
>>>
>>> Hello all,
>>>
>>> What is the best way to rearrange amplitude data in an FFT frame using
>>> pvs signal?
>>>
>>> I basically want to swap the amplitude data of one bin with another
>>> before synthesizing the FFT frame. So for instance to say that I want
>>> the amplitude of bin one to be swapped with the amplitude of bin 10
>>> and so on, but for every bin. I have tried pvsftw and vcopy but the
>>> result is very wobbly and not what I expected at all.
>>>
>>> The aim is to imitate the GRM tools spectral Warp. Is this possible?
>>>
>>> Many thanks in advance
>>>
>>> Best
>>> Peiman
>>>
>>>
>>> Send bugs reports to this list.
>>> To unsubscribe, send email sympa@lists.bath.ac.uk with body "unsubscribe
>>> csound"
>>>
>>> --
>>> This message has been scanned for viruses and
>>> dangerous content by MailScanner, and is
>>> believed to be clean.
>>
>> David Mooney: dmooney@city-net.com
>> Maxine Heller: mheller@city-net.com
>> Opaque Melodies: www.city-net.com/~moko/
>>
>>
>>
>> Send bugs reports to this list.
>> To unsubscribe, send email sympa@lists.bath.ac.uk with body "unsubscribe
>> csound"
>>
>


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