97 lines
2.3 KiB
Racket
97 lines
2.3 KiB
Racket
#lang scribble/manual
|
|
@(require (for-label racket))
|
|
|
|
@title{(pv-hainsworth-foote buffer proph propf threshold waittime)}
|
|
|
|
|
|
fft onset detector based on work described in
|
|
|
|
Hainsworth, S. (2003) Techniques for the Automated Analysis of
|
|
Musical Audio. PhD, University of Cambridge engineering dept. See
|
|
especially p128. The Hainsworth metric is a modification of the
|
|
Kullback Liebler distance.
|
|
|
|
The onset detector has general ability to spot spectral change, so
|
|
may have some ability to track chord changes aside from obvious
|
|
transient jolts, but there's no guarantee it won't be confused by
|
|
frequency modulation artifacts.
|
|
|
|
Hainsworth metric on it's own gives good results but Foote might be
|
|
useful in some situations: experimental.
|
|
|
|
buffer - fft buffer to read from
|
|
|
|
proph - What strength of detection signal from Hainsworth metric to use.
|
|
|
|
propf - What strength of detection signal from Foote metric to
|
|
use. The Foote metric is normalised to [0.0,1.0]
|
|
|
|
threshold - Threshold hold level for allowing a detection
|
|
|
|
waittime - If triggered, minimum wait until a further frame can
|
|
cause another spot (useful to stop multiple detects on
|
|
heavy signals)
|
|
|
|
Default values in sclang are: proph=0.0, propf=0.0, threshold=1.0,
|
|
waittime=0.04.
|
|
|
|
--
|
|
|
|
Just Hainsworth metric with low threshold
|
|
|
|
|
|
@racketblock[
|
|
(with-sc3
|
|
(lambda (fd)
|
|
(async fd (b-alloc 0 2048 1))))
|
|
]
|
|
|
|
|
|
@racketblock[
|
|
(let* ((source (sound-in 0))
|
|
(detect (pv-hainsworth-foote (fft* 0 source)
|
|
1.0
|
|
0.0
|
|
(mouse-x kr 0.01 1.0 1 0.1)
|
|
0.04)))
|
|
(audition
|
|
(out 0 (mul3 (sin-osc ar (mce2 440 445) 0)
|
|
(decay (mul 0.1 detect) 0.1)
|
|
0.1))))
|
|
]
|
|
|
|
Just Hainsworth metric, spot note transitions.
|
|
|
|
|
|
@racketblock[
|
|
(let* ((src (mul (lf-saw ar (mul-add (lf-noise0 kr 1) 90 400) 0) 0.5))
|
|
(dtc (pv-hainsworth-foote (fft* 0 src)
|
|
1.0
|
|
0.0
|
|
0.9
|
|
0.5))
|
|
(cmp (mul (sin-osc ar 440 0)
|
|
(decay (mul 0.1 dtc) 0.1))))
|
|
(audition
|
|
(out 0 (mul (mce2 src cmp) 0.1))))
|
|
]
|
|
|
|
Just Foote metric. Foote never triggers with threshold over 1.0,
|
|
threshold under mouse control.
|
|
|
|
|
|
@racketblock[
|
|
(let* ((src (sound-in 0))
|
|
(dtc (pv-hainsworth-foote (fft* 0 src)
|
|
0.0
|
|
1.0
|
|
(mouse-x kr 0.0 1.1 0 0.1)
|
|
0.02))
|
|
(cmp (mul (sin-osc ar 440 0)
|
|
(decay (mul 0.1 dtc) 0.1))))
|
|
(audition
|
|
(out 0 (mul (mce2 src cmp) 0.1))))
|
|
]
|
|
|
|
|
|
|