80 lines
2.3 KiB
Scheme
80 lines
2.3 KiB
Scheme
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;; (pv-hainsworth-foote buffer proph propf threshold waittime)
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;; fft onset detector based on work described in
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;; Hainsworth, S. (2003) Techniques for the Automated Analysis of
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;; Musical Audio. PhD, University of Cambridge engineering dept. See
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;; especially p128. The Hainsworth metric is a modification of the
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;; Kullback Liebler distance.
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;; The onset detector has general ability to spot spectral change, so
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;; may have some ability to track chord changes aside from obvious
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;; transient jolts, but there's no guarantee it won't be confused by
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;; frequency modulation artifacts.
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;; Hainsworth metric on it's own gives good results but Foote might be
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;; useful in some situations: experimental.
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;; buffer - fft buffer to read from
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;; proph - What strength of detection signal from Hainsworth metric to use.
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;; propf - What strength of detection signal from Foote metric to
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;; use. The Foote metric is normalised to [0.0,1.0]
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;; threshold - Threshold hold 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: proph=0.0, propf=0.0, threshold=1.0,
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;; waittime=0.04.
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;; --
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;; Just Hainsworth metric with low threshold
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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-hainsworth-foote (fft* 0 source)
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1.0
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0.0
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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 (mul3 (sin-osc ar (mce2 440 445) 0)
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(decay (mul 0.1 detect) 0.1)
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0.1))))
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;; Just Hainsworth metric, spot note transitions.
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(let* ((src (mul (lf-saw ar (mul-add (lf-noise0 kr 1) 90 400) 0) 0.5))
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(dtc (pv-hainsworth-foote (fft* 0 src)
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1.0
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0.0
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0.9
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0.5))
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(cmp (mul (sin-osc ar 440 0)
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(decay (mul 0.1 dtc) 0.1))))
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(audition
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(out 0 (mul (mce2 src cmp) 0.1))))
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;; Just Foote metric. Foote never triggers with threshold over 1.0,
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;; threshold under mouse control.
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(let* ((src (sound-in 0))
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(dtc (pv-hainsworth-foote (fft* 0 src)
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0.0
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1.0
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(mouse-x kr 0.0 1.1 0 0.1)
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0.02))
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(cmp (mul (sin-osc ar 440 0)
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(decay (mul 0.1 dtc) 0.1))))
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(audition
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(out 0 (mul (mce2 src cmp) 0.1))))
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