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;nyquist plug-in
;version 4
;type process
;preview linear
;preview selection
;categories "http://lv2plug.in/ns/lv2core#MixerPlugin"
;name "Adjustable Fade..."
;action "Applying Fade..."
;author "Steve Daulton"
;copyright "Released under terms of the GNU General Public License version 2"
;; adjustable-fade.ny by Steve Daulton Dec 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 type "Fade Type" choice "Fade Up,Fade Down,S-Curve Up,S-Curve Down" 0
;control curve "Mid-fade Adjust (%)" real "" 0 -100 100
;control units "Start/End as" choice "% of Original,dB Gain" 0
;control gain0 "Start (or end)" float-text "" 0 nil nil
;control gain1 "End (or start)" float-text "" 100 nil nil
;control preset " Handy Presets\n(override controls)" choice "None Selected,Linear In,Linear Out,Exponential In,Exponential Out,Logarithmic In,Logarithmic Out,Rounded In,Rounded Out,Cosine In,Cosine Out,S-Curve In,S-Curve Out" 0
(defun get-input (sig)
"Preview takes the entire selection so that we know the correct
selection length, but preview only needs to process preview length."
;; (if *previewp* sig (multichan-expand #'trim-input sig)))
(if (get '*track* 'view) ;NIL if preview
sig
(multichan-expand #'trim-input sig)))
(defun trim-input (sig)
"Trim input when previewing."
(let ((dur (min (get-duration 1)
(get '*project* 'preview-duration))))
(setf sig (extract-abs 0 dur *track*))))
;;; invalid values
(defun check-values (x y)
(if (= units 0) ;percentage values
(cond
((or (< x 0)(< y 0))
(throw 'err (format nil "~aPercentage values cannot be negative." err)))
((or (> x 1000)(> y 1000))
(throw 'err (format nil "~aPercentage values cannot be more than 1000 %." err))))
(cond ;dB values
((or (> x 100)(> y 100))
(throw 'err (format nil "~adB values cannot be more than +100 dB.~%~%~
Hint: 6 dB doubles the amplitude~%~
\t-6 dB halves the amplitude." err))))))
;;; select and apply fade
(defun fade (sig type curve g0 g1)
(check-values gain0 gain1)
(mult (get-input sig)
(case preset
(0 (case type ; Custom fade
(0 (simple (min g0 g1) (max g0 g1) curve))
(1 (simple (max g0 g1) (min g0 g1) curve))
(2 (raised-cos (min g0 g1)(max g0 g1) curve))
(T (raised-cos (max g0 g1) (min g0 g1) curve))))
(1 (linear 0 1)) ; Linear In
(2 (linear 1 0)) ; Linear Out
(3 (log-exp-curve -60 0)) ; Exponential In
(4 (log-exp-curve -60 1)) ; ExponentialOut
(5 (log-exp-curve 15.311 0)) ; Logarithmic In
(6 (log-exp-curve 15.311 1)) ; Logarithmic Out
(7 (simple-curve 0 1 0.5)) ; Rounded In
(8 (simple-curve 1 0 0.5)) ; Rounded Out
(9 (cosine-curve 0 1)) ; Cosine In
(10 (cosine-curve 1 0)) ; Cosine Out
(11 (raised-cos 0 1 0.0)) ; S-Curve In
(t (raised-cos 1 0 0.0))))) ; S-Curve Out
;;; Simple Curve:
;;; Use cosine for + values and linear for -ve.
(defun simple (g0 g1 curve)
(cond
((= g0 g1) g0) ; amplify
((and (> curve 0)(< curve 0.5)) ; +ve curve less than 0.5, lin to cosine
(let ((curve (* curve 2)))
(sim
(mult (- 1 curve)
(scale-curve g0 g1 (linear g0 g1))) ; linear
(mult curve
(scale-curve g0 g1 (cosine-curve g0 g1)))))) ; cosine curve
((> curve 0)
(cos-curve g0 g1 (- 1.5 curve))) ; +ve curve > 0.5
(t (simple-curve g0 g1 (- 1 (* 2 curve)))))) ; -ve curve
;;; linear fade to the power of pow
(defun simple-curve (g0 g1 pow)
(curve-adjust g0 g1 pow
(linear g0 g1)))
;;; cosine fade to the power of pow
(defun cos-curve (g0 g1 pow)
(curve-adjust g0 g1 pow
(cosine-curve g0 g1)))
(defun curve-adjust (g0 g1 pow env)
(scale-curve g0 g1
(if (= pow 1)
env
(snd-exp
(mult pow
(snd-log env))))))
;;; scale curves to min, max
(defun scale-curve (g0 g1 env)
(sum (min g0 g1)
(mult (abs (- g0 g1)) env)))
;;; cosine curve
(defun cosine-curve (g0 g1)
(let ((step (hz-to-step (/ 0.25 (get-duration 1))))
(phase (if (> g0 g1) 90 0)))
(osc step 1 *sine-table* phase)))
;;; linear fade in, out
(defun linear (g0 g1)
(control-srate-abs *sound-srate*
(if (> g0 g1) ; g0 = g1 does not occur here.
(pwlv 1 1 0) ; fade out
(pwlv 0 1 1)))) ; else fade in
;;; raised cosine fades
(defun raised-cos (g0 g1 curve)
(setq curve
(if (> curve 0)
(exp-scale-mid (* 2 curve)) ; mid-point -3dB @ Adjust = 50%
(exp-scale-mid (* 1.63 curve)))) ; mid-point -12dB @ Adjust = -50%
(setf env
(control-srate-abs *sound-srate* ; sound srate required for accuracy.
(cond
((= g0 g1) g0) ; amplify
((> g0 g1) ; fade down
(snd-exp
(mult (pwlv (- 1 curve) 1 1)
(snd-log (raised-cosin 90)))))
(t (snd-exp ; fade up
(mult (pwlv 1 1 (- 1 curve))
(snd-log (raised-cosin -90))))))))
(sum (min g0 g1)
(mult (abs (- g0 g1)) env)))
;;; raised cosine curve
(defun raised-cosin (phase)
(let ((hz (hz-to-step (/ (get-duration 2)))))
(mult 0.5
(sum 1
(osc hz 1 *sine-table* phase)))))
;;; log or exponential curve scaled 0 to 1
;;; x is the minimum level in dB before scaling
(defun log-exp-curve (x direction)
(control-srate-abs *sound-srate*
(let ((x (db-to-linear x)))
;; If direction=0 fade-in else fade-out
(if (= direction 0)
(setf env (pwev x 1 1))
(setf env (pwev 1 1 x)))
(mult (/ (- 1 x)) ; normalize to 0 dB
(diff env x))))) ; drop down to silence
;;; curve scaling for S-curve
(defun exp-scale-mid (x)
(let ((e (exp 1.0)))
(/ (- (exp (- 1 x)) e)
(- 1 e))))
(defmacro gainscale (gain type)
`(setf ,gain
(if (= ,type 0) ; percent
(/ ,gain 100.0)
(db-to-linear ,gain))))
(setf curve (/ curve 100.0))
(setf gain0 (gainscale gain0 units))
(setf gain1 (gainscale gain1 units))
(setf err "Error\n\n")
(catch 'err (fade *track* type curve gain0 gain1))