41 lines
1.3 KiB
Scheme
41 lines
1.3 KiB
Scheme
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;; (pv-jensen-andersen buffer propsc prophfe prophfc propsf threshold waittime)
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fft feature detector for onset detection based on work described in
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Jensen,K. & Andersen, T. H. (2003). Real-time Beat Estimation Using
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Feature Extraction. in Proceedings of the Computer Music Modeling and
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Retrieval Symposium, Lecture Notes in Computer Science. springer
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Verlag.
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First order derivatives of the features are taken. Threshold may
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need to be set low to pick up on changes.
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buffer - fft buffer to read from.
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propsc - Proportion of spectral centroid feature.
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prophfe - Proportion of high frequency energy feature.
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prophfc - Proportion of high frequency content feature.
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propsf - Proportion of spectral flux feature.
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threshold - Threshold level for allowing a detection
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waittime - If triggered, minimum wait until a further frame can
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cause another spot (useful to stop multiple detects on
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heavy signals)
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Default values in sclang are: propsc=0.25, prophfe=0.25,
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prophfc=0.25, propsf=0.25, threshold=1.0, waittime=0.04.
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|#
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(with-sc3
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(lambda (fd)
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(async fd (b-alloc 0 2048 1))))
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(let* ((source (sound-in 0))
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(detect (pv-jensen-andersen (fft* 0 source)
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0.25 0.25 0.25 0.25
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(mouse-x kr 0.01 1.0 1 0.1)
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0.04)))
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(audition
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(out 0 (mul (sin-osc ar (mce2 440 445) 0)
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(decay (mul 0.1 detect) 0.1)))))
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