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audacity/plug-ins/beat.ny
Steve Daulton feb35a2601 Update beatfinder to version 4
No changes to algorithm or behaviour, but removed duplicate resampling.
2019-06-09 16:57:40 +01:00

45 lines
1.3 KiB
Common Lisp

$nyquist plug-in
$version 4
$type analyze
$name (_ "Beat Finder")
$manpage "Beat_Finder"
$action (_ "Finding beats...")
$author (_ "Audacity")
$release 2.3.2
$copyright (_ "Released under terms of the GNU General Public License version 2")
;; 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:
;; https://wiki.audacityteam.org/wiki/Nyquist_Plug-ins_Reference
$control thresval (_ "Threshold Percentage") int "" 65 5 100
(setf threshold (/ thresval 100.0))
(defun mix-to-mono (sig)
(if (arrayp sig)
(sum (aref sig 0) (aref sig 1))
sig))
(defun bass-tracker (sig)
(let* ((bass (lp sig 50))
;(snd-follow sound floor risetime falltime lookahead)
(follower (snd-follow bass 0.001 0.01 0.1 512)))
(force-srate 1000 (lp follower 10))))
(let ((beats (bass-tracker (mix-to-mono *track*))))
(setf peak-sig (peak beats ny:all))
(setf threshold (* threshold peak-sig))
(do ((time 0.0 (+ time 0.001))
(val (snd-fetch beats) (snd-fetch beats))
(flag T)
labels)
((not val) labels)
(when (and flag (> val threshold))
(push (list time "B") labels))
(setf flag (< val threshold))))