/usr/share/audacity/plug-ins/vocoder.ny is in audacity-data 2.0.5-1ubuntu3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 | ;nyquist plug-in
;version 3
;type process
;categories "http://lv2plug.in/ns/lv2core#SpectralPlugin"
;name "Vocoder..."
;action "Processing Vocoder..."
;; vocoder.ny by Edgar-RFT
;; a bit of code added by David R. Sky
;; GUI update by Steve Daulton July 2012.
;; Released under terms of the GNU General Public License version 2:
;; http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
;;
;; For information about writing and modifying Nyquist plug-ins:
;; http://wiki.audacityteam.org/wiki/Nyquist_Plug-ins_Reference
;control dst "Distance: (1 to 120, default = 20)" real "" 20 1 120
;control mst "Output choice" choice "both channels, right only" 0
;control bands "Number of vocoder bands" int "" 40 10 240
;control track-vl "Amplitude of original audio (percent)" real "" 100 0 100
;control noise-vl "Amplitude of white noise (percent)" real "" 0 0 100
;control radar-vl "Amplitude of Radar Needles (percent)" real "" 0 0 100
;control radar-f "Frequency of Radar Needles (Hz)" real "" 30 1 100
; maybe the code once again has to be changed into _one_ local let-binding
; if you have lots of nyquist "[gc:" messages try this:
; (expand 100) ; gives Xlisp more memory but I have noticed no speed difference
; number of octaves between 20hz and 20khz
(setf octaves (/ (log 1000.0) (log 2.0)))
; convert octaves to number of steps (semitones)
(setf steps (* octaves 12.0))
; interval - number of steps per vocoder band
(setf interval (/ steps bands))
; Some useful calculations but not used in this plugin
; half tone distance in linear
; (print (exp (/ (log 2.0) 12)))
; octave distance in linear
; (print (exp (/ (log 1000.0) 40)))
; The Radar Wavetable
; make *radar-table* a global variable.
(setf contol-dummy *control-srate*) ; save old *control-srate*
(set-control-srate *sound-srate*)
(setf *radar-table* (pwl (/ 1.0 *control-srate*) 1.0 ; 1.0 after 1 sample
(/ 2.0 *control-srate*) 0.0 ; 0.0 after 2 samples
(/ 1.0 radar-f))) ; stay 0.0 until end of the period
(set-control-srate contol-dummy) ; restore *control-srate*
; make *radar-table* become a nyquist wavetable of frequency radar-f
(setf *radar-table* (list *radar-table* (hz-to-step radar-f) T))
; increase the volume of the audacity track in the middle of the slider
; the sqrt trick is something like an artifical db scaling
(setf track-vol (sqrt (/ track-vl 100.0)))
; decrease the volume of the white noise in the middle of the slider
; the expt trick is an inverse db scaling
(setf noise-vol (expt (/ noise-vl 100.0) 2.0))
; also increase the volume of the needles in the middle of the slider
(setf radar-vol (sqrt (/ radar-vl 100.0)))
; here you can switch the tracks on and off for bug tracking
; (setf radar-vol 0)
; (setf noise-vol 0)
; (setf track-vol 0)
; The Mixer
; calculate duration of audacity selection
(setf duration (/ len *sound-srate*))
; if track volume slider is less than 100 percent decrease track volume
(if (< track-vl 100) (setf s (vector (aref s 0) (scale track-vol (aref s 1)))))
; if radar volume slider is more than 0 percent add some radar needles
(if (> radar-vl 0) (setf s (vector (aref s 0) (sim (aref s 1)
(scale radar-vol (osc (hz-to-step radar-f) duration *radar-table*))))))
; if noise volume slider is more than 0 percent add some white noise
(if (> noise-vl 0) (setf s (vector (aref s 0) (sim (aref s 1)
(scale noise-vol (noise duration))))))
; The Vocoder
(defun vocoder ()
(let ((p (+ (hz-to-step 20) (/ interval 2.0))) ; midi step of 20 Hz + offset
f ; we can leave f initialized to NIL
(q (/ (sqrt 2.0) (/ octaves bands))) ; explanation still missing
(result 0)) ; must be initialized to 0 because you cannot sum to NIL
(dotimes (i bands)
(setf f (step-to-hz p))
(setf result (sum result
(bandpass2 (mult (lowpass8
(s-max (bandpass2 (aref s 0) f q)
(scale -1 (bandpass2 (aref s 0) f q))) (/ f dst))
(bandpass2 (aref s 1) f q)) f q)))
(setf p (+ p interval)))
result))
; The Program
(if (arrayp s) (let ()
(cond ((= mst 1) (vector (aref s 0) (setf (aref s 1) (vocoder))))
((= mst 0) (setf s (vocoder))))
(cond ((= mst 1) (setq peakamp (peak (aref s 1) ny:all)))
((= mst 0) (setq peakamp (peak s ny:all))))
(cond ((= mst 1) (vector (aref s 0) (setf (aref s 1)
(scale (/ 1.0 peakamp) (aref s 1)))))
((= mst 0) (setf s (scale (/ 1.0 peakamp) s))))
s))
|