/usr/share/audacity/plug-ins/delay.ny is in audacity-data 2.1.2-1.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 | ;nyquist plug-in
;version 3
;type process
;preview linear
;categories "http://lv2plug.in/ns/lv2core#DelayPlugin"
;name "Delay..."
;action "Applying Delay Effect..."
;author "Steve Daulton"
;copyright "Released under terms of the GNU General Public License version 2"
;; by Steve Daulton, July 2012.
;; based on 'Delay' by David R. Sky
;; 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 delay-type "Delay type" choice "regular,bouncing ball,reverse bouncing ball" 0
;control dgain "Delay level per echo (dB)" real "" -6 -30 1
;control delay "Delay time (seconds)" real "" 0.3 0 5
;control pitch-type "Pitch change effect" choice "Pitch/Tempo,LQ Pitch Shift" 0
;control shift "Pitch change per echo (semitones)" real "" 0 -2 2
;control number "Number of echoes" int "" 5 1 30
;control constrain "Allow duration to change" choice "Yes,No" 0
;; The default pitch shift effect is a simple resampling,
;; so both pitch and tempo of the delayed audio will change
;; [as in Audacity's Change Speed effect].
;; LQ Pitch Shift (Low Quality) changes the pitch without
;; changing the tempo, but the sound quality is not very good
;; and tends to cause a short echo effect which can be quite
;; noticeable on percussive sounds though may be acceptable
;; on other sounds.
(setf err "") ; initialise error message
(defun err-chk (arg min max)
(if (or (< arg min) (> arg max))
T nil))
(when (err-chk number 1 50)(setq err (format nil
"Number of echoes '~a' outside valid range 1 to 50.~%~a"
number err)))
(when (err-chk shift -12 12)(setq err (format nil
"Pitch change '~a' outside valid range -12 to +12 semitones.~%~a"
shift err)))
(when (err-chk delay 0 10)(setq err (format nil
"Delay time '~a' outside valid range 0 to 10 seconds.~%~a"
delay err)))
(when (err-chk dgain -30 6)(setq err (format nil
"Delay level '~a' outside valid range -30 to +6 dB.~%~a"
dgain err)))
;;; anti-alias low pass filter
(defun lp-wall (sig freq)
(do ((count 0 (1+ count))
(freq (* 0.94 freq)))
((= count 10) sig)
(setf sig (lowpass8 sig freq))))
;;; Change speed
(defun change-speed (sig shift)
(if (= shift 0) ; no pitch shift
sig
(let ((ratio (expt 0.5 (/ shift 12.0)))) ; shift value as frequency ratio
(force-srate *sound-srate*
(stretch-abs ratio (sound sig))))))
;;; pitch shift audio
(defun p-shift (sig shift)
(if (= shift 0) ; no pitch shift
sig
(let ((sig (force-srate 44100 sig)) ; pitshift quality best at 44100
; anti-alias filter frequency
(minrate (* 0.5 (min *sound-srate* 44100)))
(ratio (expt 0.5 (/ shift -12.0)))) ; shift value as frequency ratio
(force-srate *sound-srate* ; convert back to correct rate
(progv '(*sound-srate*) (list 44100) ; pitshift requires rates to match
(cond
((> shift 5) ; reduce aliasing
(pitshift (lp-wall sig (/ minrate ratio)) ratio 1))
((< shift -2)
(pitshift (hp sig 20) ratio 1)) ; reduce sub-sonic frequencies
(T (pitshift sig ratio 1))))))))
;;; apply effects to echo
(defun modify (sig num gain shift p-type)
(let ((gain (db-to-linear (* num gain)))
(shift (* num shift)))
(if (= p-type 0)
(mult gain (change-speed sig shift))
(mult gain (p-shift sig shift)))))
;;; compute echoes
(defun delays (sound gain delay shift num type mod)
(let ((echo (s-rest 0)))
(do ((count 1 (1+ count))
(dly 0))
((> count num)(sim echo sound))
(setq dly
(case type
(0 (+ dly delay))
(1 (+ dly (* delay (- (1+ num) count))))
(2 (+ dly (* delay count)))))
(setf echo (sim
(at 0 (cue echo))
(at-abs dly
(cue (modify sound count gain shift mod))))))))
(defun constrain-abs (sig dur)
(extract-abs 0 dur (cue sig)))
;;; return errors or process
(if (> (length err) 0)
(format nil "Error.~%~a" err) ; return error
(let* ((delay (if (= delay-type 0) delay (/ delay number)))
(output
(multichan-expand #'delays
s dgain delay shift number delay-type pitch-type)))
(if (= constrain 1)
(multichan-expand #'constrain-abs output (get-duration 1))
output)))
|