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<p class="p1"><b>FFTPeak<span class="Apple-tab-span"> </span><span class="Apple-tab-span"> </span>Find peak value in an FFT frame</b></p>
<p class="p2"><br></p>
<p class="p3"><b><span class="Apple-tab-span"> </span># freq, mag = FFTSlope.kr(chain)</b></p>
<p class="p2"><br></p>
<p class="p3">Given an <a href="SC://FFT"><span class="s1">FFT</span></a> <b>chain</b>, this finds the bin with the strongest magnitude. It outputs the frequency of that bin, and its magnitude.<span class="Apple-converted-space"> </span>No interpolation is done on the values.</p>
<p class="p2"><br></p>
<p class="p3">This could be used as a primitive pitch detector, but in practice autocorrelation methods (as used in <a href="SC://Pitch"><span class="s2">Pitch</span></a> and <a href="../../../../../../Library/Application Support/SuperCollider/Extensions/Nick Collins/MachineListening/MachineListening Help/Tartini.help.rtf"><span class="s2">Tartini</span></a>) give more reliable pitch tracks. This simple approach gives poor resolution and robustness for that purpose. However it can be useful for other things...</p>
<p class="p2"><br></p>
<p class="p2"><br></p>
<p class="p3"><b>Example</b></p>
<p class="p2"><br></p>
<p class="p4">// Let's see how good it is at tracking the "pitch" of a sinewave!</p>
<p class="p5">s.boot;</p>
<p class="p5">b = <span class="s3">Buffer</span>.alloc(s,2048,1);</p>
<p class="p5">(</p>
<p class="p5">x = {</p>
<p class="p5"><span class="s4">var</span> in, chain, pitch, freq, mag;</p>
<p class="p6"><br></p>
<p class="p5">pitch = <span class="s4">MouseX</span>.kr(100, 1000, 1);</p>
<p class="p6"><br></p>
<p class="p5">in = <span class="s4">SinOsc</span>.ar(pitch);</p>
<p class="p6"><br></p>
<p class="p5">chain = <span class="s4">FFT</span>(b.bufnum, in);</p>
<p class="p6"><br></p>
<p class="p5"># freq, mag = <span class="s4">FFTPeak</span>.kr(chain);</p>
<p class="p6"><br></p>
<p class="p5"><span class="s4">Out</span>.ar(0, in.dup * 0.1);</p>
<p class="p6"><br></p>
<p class="p5">pitch.poll(label: <span class="s5">"Tru freq"</span>);</p>
<p class="p5">freq .poll(label: <span class="s5">"Inferred"</span>);</p>
<p class="p5">}.play(s);</p>
<p class="p5">)</p>
<p class="p6"><br></p>
<p class="p5">x.free;</p>
<p class="p6"><br></p>
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