mirror of
https://github.com/cookiengineer/audacity
synced 2025-04-30 07:39:42 +02:00
45 lines
1.4 KiB
Common Lisp
45 lines
1.4 KiB
Common Lisp
;nyquist plug-in
|
|
;version 1
|
|
;type process
|
|
;categories "http://lv2plug.in/ns/lv2core#MixerPlugin"
|
|
;name "Studio Fade Out"
|
|
;manpage "Fades#studio_fadeout"
|
|
;action "Applying Fade..."
|
|
;author "Steve Daulton"
|
|
;copyright "Released under terms of the GNU General Public License version 2"
|
|
|
|
;; StudioFadeOut.ny by Steve Daulton December 2012.
|
|
;; Released under terms of the GNU General Public License version 2:
|
|
;; http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
|
|
;;
|
|
;; Produce a smooth and musical sounding fade out.
|
|
;; Applies a sinusoidal fade out with a progressive low-pass
|
|
;; filter from full spectrum at start to 100 Hz at end.
|
|
;;
|
|
;; For information about writing and modifying Nyquist plug-ins:
|
|
;; https://wiki.audacityteam.org/wiki/Nyquist_Plug-ins_Reference
|
|
|
|
;;; sweeping low pass filter
|
|
(defun filter (sig dur)
|
|
(abs-env
|
|
;; cross-fade the filter
|
|
(let* ((nyq-hz (/ *sound-srate* 2))
|
|
(f-out (r-cos (min (/ dur 2.0) 0.5)))
|
|
(f-in (diff (snd-const 1 0 *sound-srate* dur) f-out)))
|
|
(sim
|
|
(mult f-out sig)
|
|
(mult f-in (lp sig (pwlv nyq-hz dur 100)))))))
|
|
|
|
;;; raised cosine
|
|
(defun r-cos (dur)
|
|
(abs-env
|
|
(mult 0.5
|
|
(sum 1
|
|
(osc (hz-to-step (/ (* dur 2))) dur *table* 90)))))
|
|
|
|
(let ((dur (get-duration 1)))
|
|
(cond
|
|
((< len 3) "Selection too short.\nIt must be more than 2 samples.")
|
|
((< dur 0.2) (mult s (r-cos dur)))
|
|
(t (mult (filter s dur)(r-cos dur)))))
|
|
|