Description

This opcode provides support for cross-synthesis of amplitudes and frequencies. It takes the amplitudes of one input fsig and combines with frequencies from another. It is a spectral version of the well-known channel vocoder.

Syntax

fsig pvsvoc famp, fexc, kdepth, kgain [,kcoefs]

Performance

fsig -- output pv stream

famp -- input pv stream from which the amplitudes will be extracted

fexc -- input pv stream from which the frequencies will be taken

kdepth -- depth of effect, affecting how much of the frequencies will be taken from the second fsig: 0, the output is the famp signal, 1 the output is the famp amplitudes and fexc frequencies.

kgain -- gain boost/attenuation applied to the output.

kcoefs -- number of cepstrum coefs used in spectral envelope estimation (defaults to 80).

	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 pvsvoc opcode. It uses the file pvsvoc.csd.

<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 pvsvoc.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

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

gisaw	ftgen	1, 0, 2048, 10, 1, 0.5, 0.3, 0.25, 0.2	;sawtooth-like

instr 1

asig in					;get the signal in
asyn poscil .6, 150, gisaw		;excitation signal of 150 Hz

famp pvsanal asig, 1024, 256, 1024, 1	;analyse in signal
fexc pvsanal asyn, 1024, 256, 1024, 1	;analyse excitation signal
ftps pvsvoc  famp, fexc, 1, 1		;cross it
atps pvsynth ftps			;synthesise it                      
     outs atps, atps

endin
</CsInstruments>
<CsScore>

i 1 0 10
e
</CsScore>
</CsoundSynthesizer>

The example above shows a typical cross-synthesis operation. The input signal (say a vocal sound) is used for its amplitude spectrum. An oscillator with an arbitrary complex waveform produces the excitation signal, giving the vocal sound its pitch.

Credits

New plugin in version 5

April 2005.