mirror of
https://github.com/cookiengineer/audacity
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89 lines
2.7 KiB
Common Lisp
89 lines
2.7 KiB
Common Lisp
;nyquist plug-in
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;version 4
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;type generate
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;categories "http://lv2plug.in/ns/lv2core#GeneratorPlugin"
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;preview linear
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;name "Risset Drum..."
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;manpage "Risset_Drum"
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;action "Generating Risset Drum..."
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;author "Steven Jones"
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;copyright "Released under terms of the GNU General Public License version 2"
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;; rissetdrum.ny by Steven Jones, after Jean Claude Risset.
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;; Updated by Steve Daulton July 2012 and May 2015.
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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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;; http://wiki.audacityteam.org/wiki/Nyquist_Plug-ins_Reference
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;control freq "Frequency (Hz)" real "" 100 50 2000
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;control decay "Decay (seconds)" real "" 2 0.1 60
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;control cf "Center frequency of noise (Hz)" real "" 500 100 5000
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;control bw "Width of noise band (Hz)" real "" 400 10 1000
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;control noise "Amount of noise in mix (percent)" real "" 25 0 100
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;control gain "Amplitude (0 - 1)" real "" 0.8 0 1
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(defun sanitise (val minx maxx)
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(min (max val minx) maxx))
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;; Not required with validation in Audacity 2.1.1 but left
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;; for compatibility.
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(setq freq (sanitise freq 1 (/ *sound-srate* 2)))
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(setq decay (sanitise decay 0.1 600))
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(setq cf (sanitise cf 1 (/ *sound-srate* 2)))
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(setq bw (sanitise bw 10 1000))
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(setq noise (sanitise (/ noise 100) 0 1))
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(setq gain (sanitise gain 0 1))
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;; Get length of preview
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(setq pdur
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(if (get '*track* 'view) ;NIL if preview
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decay
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(get '*project* 'preview-duration)))
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(setq *rdrum-table*
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(list
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(mult 0.17
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(sum
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(scale 1.00 (build-harmonic 10 2048))
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(scale 1.50 (build-harmonic 16 2048))
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(scale 2.00 (build-harmonic 22 2048))
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(scale 1.50 (build-harmonic 23 2048))))
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(hz-to-step 1) t))
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(defun log2 (n)
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(/ (log (float n))(log 2.0)))
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(defun percussion-env (decay)
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(let* ((half-life (expt 2.0 (- (log2 decay) 3))))
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(exp-dec 0 half-life decay)))
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(defun risset-drum (freq decay cf bw noise-gain)
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(let* ((decay2 (* decay 0.50))
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(low-note (* freq 0.10))
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(tone-gain (- 1 noise-gain)))
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(setf pink (lowpass6 (noise decay2) bw))
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(setf rdrum
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(mult tone-gain
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(osc (hz-to-step low-note) decay2 *rdrum-table*)))
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(setf noise-band
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(mult noise-gain
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(sine (hz-to-step cf) decay2)
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pink))
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(sum
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(mult
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(percussion-env decay2)
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(sum noise-band rdrum ))
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(mult tone-gain
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(percussion-env decay)
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(sine (hz-to-step freq) decay)))))
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;; Generate and normalize
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(let* ((output (risset-drum freq decay cf bw noise))
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(output (extract-abs 0 pdur output)) ; shorten if necessary for preview.
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(peakval (peak output ny:all)))
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(scale (/ gain peakval) output))
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