Help/UGens/FFT/PV_JensenAndersen.html

   1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
   2 <html>
   3 <head>
   4 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
   5 <meta http-equiv="Content-Style-Type" content="text/css">
   6 <title></title>
   7 <meta name="Generator" content="Cocoa HTML Writer">
   8 <meta name="CocoaVersion" content="949.35">
   9 <style type="text/css">
  10 p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 22.0px Helvetica}
  11 p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 12.0px Helvetica; min-height: 14.0px}
  12 p.p3 {margin: 0.0px 0.0px 0.0px 0.0px; font: 12.0px Helvetica}
  13 p.p4 {margin: 0.0px 0.0px 0.0px 0.0px; font: 10.0px Monaco; color: #5a653b}
  14 p.p5 {margin: 0.0px 0.0px 0.0px 0.0px; font: 12.0px Helvetica; color: #0021e7}
  15 p.p6 {margin: 0.0px 0.0px 0.0px 0.0px; font: 9.0px Monaco; color: #ad140d; min-height: 12.0px}
  16 p.p7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 9.0px Monaco; color: #000000; min-height: 12.0px}
  17 p.p8 {margin: 0.0px 0.0px 0.0px 0.0px; font: 9.0px Monaco; color: #bf0000}
  18 p.p9 {margin: 0.0px 0.0px 0.0px 0.0px; font: 9.0px Monaco; color: #000000}
  19 span.s1 {color: #000000}
  20 span.s2 {text-decoration: underline}
  21 span.s3 {color: #0000bf}
  22 span.Apple-tab-span {white-space:pre}
  23 </style>
  24 </head>
  25 <body>
  26 <p class="p1"><b>PV_JensenAndersen</b></p>
  27 <p class="p2"><br></p>
  28 <p class="p3">FFT feature detector for onset detection based on work described in<span class="Apple-converted-space"> </span></p>
  29 <p class="p2"><br></p>
  30 <p class="p4">Jensen,K. &amp; Andersen, T. H. (2003). Real-time Beat Estimation Using Feature Extraction.<span class="Apple-converted-space"> </span></p>
  31 <p class="p4">In Proceedings of the Computer Music Modeling and Retrieval Symposium, Lecture Notes in Computer Science. Springer Verlag.</p>
  32 <p class="p2"><br></p>
  33 <p class="p3">First order derivatives of the features are taken. Threshold may need to be set low to pick up on changes.<span class="Apple-converted-space"> </span></p>
  34 <p class="p2"><br></p>
  35 <p class="p3"><b>*ar(buffer, propsc=0.25, prophfe=0.25, prophfc=0.25, propsf=0.25, threshold=1.0, waittime=0.04)</b></p>
  36 <p class="p2"><br></p>
  37 <p class="p3"><b>buffer-</b> FFT buffer to read from.</p>
  38 <p class="p2"><br></p>
  39 <p class="p3"><b>propsc-</b> Proportion of spectral centroid feature.</p>
  40 <p class="p2"><br></p>
  41 <p class="p3"><b>prophfe-</b> Proportion of high frequency energy feature.</p>
  42 <p class="p2"><br></p>
  43 <p class="p3"><b>prophfc-</b> Proportion of high frequency content feature.</p>
  44 <p class="p2"><br></p>
  45 <p class="p3"><b>propsf-</b> Proportion of spectral flux feature.</p>
  46 <p class="p2"><br></p>
  47 <p class="p3"><b>threshold-</b> Threshold level for allowing a detection</p>
  48 <p class="p2"><br></p>
  49 <p class="p3"><b>waittime-</b> If triggered, minimum wait until a further frame can cause another spot (useful to stop multiple detects on heavy signals)</p>
  50 <p class="p2"><br></p>
  51 <p class="p5"><span class="s1">See also <a href="FFT Overview.html"><span class="s2">FFT Overview</span></a>.</span></p>
  52 <p class="p2"><br></p>
  53 <p class="p6"><br></p>
  54 <p class="p7"><br></p>
  55 <p class="p8">// Examples</p>
  56 <p class="p7"><br></p>
  57 <p class="p8">// external sound in<span class="Apple-tab-span"> </span><span class="Apple-tab-span">    </span></p>
  58 <p class="p9">(</p>
  59 <p class="p9">{</p>
  60 <p class="p9"><span class="Apple-tab-span">     </span><span class="s3">var</span> source1, detect;</p>
  61 <p class="p9"><span class="Apple-tab-span">     </span>source1 = <span class="s3">SoundIn</span>.ar(0);<span class="Apple-converted-space"> </span></p>
  62 <p class="p9"><span class="Apple-tab-span">     </span>detect = <span class="s3">PV_JensenAndersen</span>.ar(<span class="s3">FFT</span>(<span class="s3">LocalBuf</span>(2048), source1), threshold:<span class="s3">MouseX</span>.kr(0.1,1.0));</p>
  63 <p class="p9"><span class="Apple-tab-span">     </span><span class="s3">SinOsc</span>.ar([440, 445], 0, <span class="s3">Decay</span>.ar(0.1 * detect, 0.1));</p>
  64 <p class="p9">}.play;<span class="Apple-tab-span">      </span></p>
  65 <p class="p9">)</p>
  66 <p class="p7"><br></p>
  67 <p class="p7"><br></p>
  68 <p class="p8">// using test sound:<span class="Apple-converted-space"> </span></p>
  69 <p class="p8">// mouse y is difficulty, mouse x is threshold</p>
  70 <p class="p9">(</p>
  71 <p class="p9">{</p>
  72 <p class="p9"><span class="Apple-tab-span">     </span><span class="s3">var</span> source1, detect, difficulty, rate;</p>
  73 <p class="p9"><span class="Apple-tab-span">     </span>rate = <span class="s3">LFNoise1</span>.kr(0.3).exprange(1, 5);</p>
  74 <p class="p9"><span class="Apple-tab-span">     </span>difficulty = <span class="s3">MouseY</span>.kr(0.01, 0.4, 1);</p>
  75 <p class="p9"><span class="Apple-tab-span">     </span>source1 = <span class="s3">Decay</span>.ar(<span class="s3">Impulse</span>.ar(rate), 0.5 / rate, 1 - difficulty, difficulty);</p>
  76 <p class="p9"><span class="Apple-tab-span">     </span>source1 = source1 * <span class="s3">PinkNoise</span>.ar(1.dup);</p>
  77 <p class="p9"><span class="Apple-tab-span">     </span>detect = <span class="s3">PV_JensenAndersen</span>.ar(<span class="s3">FFT</span>(<span class="s3">LocalBuf</span>(2048), source1), threshold: <span class="s3">MouseX</span>.kr(0.1,1.0));</p>
  78 <p class="p9"><span class="Apple-tab-span">     </span><span class="s3">SinOsc</span>.ar([440, 445], 0, <span class="s3">Decay</span>.ar(0.1 * detect, 0.1)) + source1;</p>
  79 <p class="p9">}.play;<span class="Apple-tab-span">      </span></p>
  80 <p class="p9">)</p>
  81 <p class="p7"><br></p>
  82 <p class="p7"><br></p>
  83 </body>
  84 </html>