pvsvoc
Prev | Orchestra Opcodes and Operators | Next

## pvsvoc

pvsvoc — Combine the spectral envelope of one fsig with the excitation (frequencies) of another.

## 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.

Example 823. Example of the pvsvoc opcode.

See the sections Real-time Audio and Command Line Flags for more information on using command line flags.

    <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

Author: Victor Lazzarini
April 2005

New plugin in version 5

April 2005.

Prev | Up | Next
pvstrace | Home | pvsynth