mirror of
https://github.com/cookiengineer/audacity
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96 lines
3.2 KiB
Common Lisp
96 lines
3.2 KiB
Common Lisp
$nyquist plug-in
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$version 4
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$type analyze
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$debugbutton false
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$debugflags trace
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$name (_ "Silence Finder")
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$manpage "Silence_Finder"
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$author (_ "Steve Daulton")
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$release 2.4.0
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$copyright (_ "Released under terms of the GNU General Public License version 2")
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;; Original version by Alex S. Brown, PMP (http://www.alexsbrown.com)
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;;
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;; Released under terms of the GNU General Public License version 2:
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;; http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
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;;
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;; For information about writing and modifying Nyquist plug-ins:
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;; https://wiki.audacityteam.org/wiki/Nyquist_Plug-ins_Reference
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$control threshold (_ "Treat audio below this level as silence (dB)") float "" -30 -100 0
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$control min-silence (_ "Minimum duration of silence (seconds)") float "" 1.0 0.1 5.0
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$control label-position (_ "Label placement (seconds before silence ends)") float "" 0.3 0.0 1.0
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(setf threshold (db-to-linear threshold))
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; Label is usually offset to earlier time.
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(setf label-position (- label-position))
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;i18n-hint: Abbreviation of "Silence".
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(setf *labeltxt* (_ "S"))
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(setf *labels* NIL)
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(defun to-mono (sig)
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;;; coerce sig to mono.
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(if (arrayp sig)
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(s-max (s-abs (aref sig 0))
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(s-abs (aref sig 1)))
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sig))
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(defun reduce-srate (sig)
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;;; Reduce sample rate to (about) 100 Hz.
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(let ((ratio (round (/ *sound-srate* 100))))
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(snd-avg sig ratio ratio OP-PEAK)))
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(defun add-label (samples srate offset)
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;;; Add new label to *labels*
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(let ((time (+ (/ samples srate) offset)))
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(push (list time *labeltxt*) *labels*)))
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(defun format-time (s)
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;;; format time in seconds as h m s.
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(let* ((hh (truncate (/ s 3600)))
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(mm (truncate (/ s 60))))
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;i18n-hint: hours minutes and seconds. Do not translate "~a".
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(format nil (_ "~ah ~am ~as")
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hh (- mm (* hh 60)) (rem (truncate s) 60))))
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(defun label-silences (sig)
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;;; Label silences that are longer than 'min-len' samples.
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(let* ((sample-count 0)
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(sil-count 0)
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(srate (snd-srate sig))
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(min-len (* min-silence srate)))
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(do ((val (snd-fetch sig) (snd-fetch sig)))
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((not val) sil-count)
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(cond
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((< val threshold)
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(incf sil-count))
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(t (when (> sil-count min-len)
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(add-label sample-count srate label-position))
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(setf sil-count 0)))
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(incf sample-count))
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;; If long trailing silence, add final label at 'min-silence' AFTER last sound.
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(when (> sil-count min-len)
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(setf final-silence (- sample-count sil-count))
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(add-label final-silence srate min-silence))
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*labels*))
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;; Bug 2352: Throw error if selection too long for Nyquist.
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(let* ((dur (- (get '*selection* 'end)
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(get '*selection* 'start)))
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(samples (* dur *sound-srate*))
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(max-samples (1- (power 2 31))))
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(if (>= samples max-samples)
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(format nil "Error.~%Selection must be less than ~a."
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(format-time (/ max-samples *sound-srate*)))
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;; Selection OK, so run the analyzer.
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(let ((sig (reduce-srate (to-mono *track*))))
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(setf *track* nil) ;free *track* from memory
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(if (label-silences sig)
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*labels*
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(_ "No silences found.
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Try reducing the silence level and
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the minimum silence duration.")))))
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