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pvscross

Performs cross-synthesis between two source fsigs.

Syntax

fsig = pvscross(fsrc, fdest, kamp1, kamp2)

fsig pvscross fsrc, fdest, kamp1, kamp2

Performance

The operation of this opcode is identical to that of pvcross (q.v.), except in using fsig_s rather than analysis files, and the absence of spectral envelope preservation. The amplitudes from _fsrc and fdest (using scale factors kamp1 for fsrc and kamp2 for fdest) are applied to the frequencies of fsrc. kamp1 and kamp2 must not exceed the range 0 to 1.

With this opcode, cross-synthesis can be performed on real-time audio input, by using pvsanal to generate fsrc and fdest. These must have the same format.

⚠ Warning

It is unsafe to use the same f-variable for both input and output of pvs opcodes. Using the same one might lead to undefined behavior on some opcodes. Use a different one on the left and right sides of the opcode.

Examples

Here is an example of the use of the pvscross opcode. It uses the file pvscross.csd.

Example of the _pvscross_ opcode.
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<CsoundSynthesizer>
<CsOptions>
; Select audio/midi flags here according to platform
-odac    ;;;realtime audio out
;-iadc    ;;;uncomment -iadc if realtime audio input is needed too
; For Non-realtime ouput leave only the line below:
;-o pvscross.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

sr = 44100
ksmps = 32
nchnls = 2
0dbfs  = 1

; by Menno Knevel 2021, after an example by joachim heintz 2009

instr 1
  ipermut  = p4                                                  ; 1 = change order of soundfiles
  ifftsize = 1024
  ioverlap = ifftsize / 4
  iwinsize = ifftsize
  iwinshape = 1                                                  ; von-Hann window
  Sfile1 = "oboe.aiff"
  Sfile2 = "finneganswake1.flac"
  ain1   = diskin2:a(Sfile1, .5, 0, 1)
  ain2   = diskin2:a(Sfile2, 1, 0, 1)                             ; the wave plays 4 x faster and higher
  fftin1 = pvsanal(ain1, ifftsize, ioverlap, iwinsize, iwinshape) ; fft-analysis of file 1
  fftin2 = pvsanal(ain2, ifftsize, ioverlap, iwinsize, iwinshape) ; fft-analysis of file 2
  ktrans = linseg(0, p3*.2, 0, p3*.6, p5, p3*.2, p5)              ; transitions
  if ipermut == 1 then
    fcross = pvscross(fftin2, fftin1, ktrans, 1 - ktrans)
  else
    fcross = pvscross(fftin1, fftin2, ktrans, 1 - ktrans)
  endif
  aout = pvsynth(fcross)
  outs(aout, aout)
endin

</CsInstruments>
<CsScore>
; use only first portion of sample (=p5)
i 1 0 12.7   0    0     ; frequencies from the oboe, no transition
i 1 14 12.7  1    0     ; frequencies from the voice, no transition
; transition over total sample (=p5)
i 1 28 12.7  0    1    ; frequencies from the oboe, amplitude transition from voice to oboe
i 1 42 12.7  1    1    ; frequencies from the voice, amplitude transition from oboe to voice
e
</CsScore>
</CsoundSynthesizer>

See also

Tools for Real-time Spectral Processing (pvs opcodes)

Credits

Author: Richard Dobson
August 2001

November 2003. Thanks to Kanata Motohashi, fixed the link to the pvcross opcode.

New in version 4.13