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pvsfreeze

Freeze the amplitude and frequency time functions of a pv stream according to a control-rate trigger.

This opcodes 'freezes' the evolution of pvs stream by locking into steady amplitude and/or frequency values for each bin. The freezing is controlled, independently for amplitudes and frequencies, by a control-rate trigger, which switches the freezing 'on' if equal to or above 1 and 'off' if below 1.

Syntax

fsig pvsfreeze fsigin, kfreeza, kfreezf

Performance

fsig -- output pv stream

fsigin -- input pv stream.

kfreeza -- freezing switch for amplitudes. Freezing is on if above or equal to 1 and off if below 1.

kfcf -- freezing switch for frequencies. Freezing is on if above or equal to 1 and off if below 1.

⚠ 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

asig  in                                       ; input
ktrig oscil     1.5, 0.25, 1                   ; trigger
fim   pvsanal   asig1, 1024, 256, 1024, 0      ; pvoc analysis 
fou   pvsfreeze fim, abs(ktrig), abs(ktrig)    ; regular 'freeze' of spectra
aout  pvsynth   fou                            ; pvoc synthesis

In the example above the input signal will be regularly 'frozen' for a short while, as the trigger rises above 1 about every two seconds.

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

Example of the _pvsfreeze_ opcode.
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<CsoundSynthesizer>
<CsOptions>
; Select audio/midi flags here according to platform
; Audio out   Audio in
-odac  ;;;realtime audio out
; For Non-realtime ouput leave only the line below:
; -o pvsfreeze.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

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

;; example written by joachim heintz 2009

seed            0

instr 1

ifftsize        = 1024
ioverlap        = ifftsize / 4
iwinsize        = ifftsize
iwinshape       = 1     ; von-Hann window
Sfile1          = "fox.wav"
ain             soundin Sfile1
kfreq           randomh .7, 1.1, 3; probability of freezing freqs: 1/4
kamp            randomh .7, 1.1, 3; idem for amplitudes
fftin           pvsanal ain, ifftsize, ioverlap, iwinsize, iwinshape; fft-analysis of file
freeze          pvsfreeze       fftin, kamp, kfreq; freeze amps or freqs independently
aout            pvsynth freeze; resynthesize
                outs aout, aout
endin

</CsInstruments>
<CsScore>
r 10
i 1 0 2.757
e
</CsScore>
</CsoundSynthesizer>

See also

Tools for Real-time Spectral Processing (pvs opcodes)

Credits

Author: Victor Lazzarini
May 2006

New plugin in version 5

May 2006.