106 lines
2.4 KiB
Text
106 lines
2.4 KiB
Text
|
class:: PV_HainsworthFoote
|
||
|
|
summary:: FFT onset detector.
|
||
|
|
related:: Classes/PV_JensenAndersen
|
||
|
|
categories:: UGens>FFT
|
||
|
|
|
||
|
|
|
||
|
|
Description::
|
||
|
|
|
||
|
|
FFT onset detector based on work described in emphasis:: 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.
|
||
|
|
|
||
|
|
|
||
|
|
classmethods::
|
||
|
|
private:: categories
|
||
|
|
|
||
|
|
method::ar
|
||
|
|
|
||
|
|
argument::buffer
|
||
|
|
|
||
|
|
FFT buffer.
|
||
|
|
|
||
|
|
|
||
|
|
argument::proph
|
||
|
|
|
||
|
|
What strength of detection signal from Hainsworth metric to use.
|
||
|
|
|
||
|
|
|
||
|
|
argument::propf
|
||
|
|
|
||
|
|
What strength of detection signal from Foote metric to use. The
|
||
|
|
Foote metric is normalised to (0..1).
|
||
|
|
|
||
|
|
|
||
|
|
argument::threshold
|
||
|
|
|
||
|
|
Threshold hold level for allowing a detection.
|
||
|
|
|
||
|
|
|
||
|
|
argument::waittime
|
||
|
|
|
||
|
|
If triggered, minimum wait until a further frame can cause
|
||
|
|
another spot (useful to stop multiple detects on heavy signals).
|
||
|
|
|
||
|
|
|
||
|
|
Examples::
|
||
|
|
|
||
|
|
code::
|
||
|
|
|
||
|
|
//just Hainsworth metric with low threshold
|
||
|
|
(
|
||
|
|
SynthDef(\fftod, {
|
||
|
|
var source1, detect;
|
||
|
|
source1= AudioIn.ar(1);
|
||
|
|
detect= PV_HainsworthFoote.ar(FFT(LocalBuf(2048),source1), 1.0, 0.0);
|
||
|
|
Out.ar(0,SinOsc.ar([440,445],0,Decay.ar(0.1*detect,0.1)));
|
||
|
|
}).play(s);
|
||
|
|
)
|
||
|
|
|
||
|
|
|
||
|
|
//spot note transitions
|
||
|
|
(
|
||
|
|
SynthDef(\fftod, {
|
||
|
|
var source1, detect;
|
||
|
|
source1= LFSaw.ar(LFNoise0.kr(1,90,400),0,0.5);
|
||
|
|
detect= PV_HainsworthFoote.ar(FFT(LocalBuf(2048),source1), 1.0, 0.0, 0.9, 0.5);
|
||
|
|
Out.ar(0,Pan2.ar(source1,-1.0)+ Pan2.ar(SinOsc.ar(440,0,Decay.ar(0.1*detect,0.1)),1.0));
|
||
|
|
}).play(s);
|
||
|
|
)
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
//Foote solo- never triggers with threshold over 1.0, threshold under mouse control
|
||
|
|
(
|
||
|
|
SynthDef(\fftod, {
|
||
|
|
var source1, detect;
|
||
|
|
source1= AudioIn.ar(1);
|
||
|
|
detect= PV_HainsworthFoote.ar(FFT(LocalBuf(2048),source1), 0.0, 1.0, MouseX.kr(0.0,1.1), 0.02);
|
||
|
|
Out.ar(0,Pan2.ar(source1,-1.0)+ Pan2.ar(SinOsc.ar(440,0,Decay.ar(0.1*detect,0.1)),1.0));
|
||
|
|
}).play(s);
|
||
|
|
)
|
||
|
|
|
||
|
|
|
||
|
|
//compare to Amplitude UGen
|
||
|
|
(
|
||
|
|
SynthDef(\fftod, {
|
||
|
|
var source1, detect;
|
||
|
|
source1= AudioIn.ar(1);
|
||
|
|
detect= (Amplitude.ar(source1)) > (MouseX.kr(0.0,1.1));
|
||
|
|
Out.ar(0,Pan2.ar(source1,-1.0)+ Pan2.ar(SinOsc.ar(440,0,Decay.ar(0.1*detect,0.1)),1.0));
|
||
|
|
}).play(s);
|
||
|
|
)
|
||
|
|
|
||
|
|
::
|
||
|
|
|