Help/UGens/Info/SubsampleOffset.html

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  29 <p class="p1"><span class="s1"><b>SubsampleOffset</b></span><span class="s2"><span class="Apple-tab-span">      </span><span class="Apple-tab-span">    </span></span><b>offset from synth start within one sample</b></p>
  30 <p class="p2"><br></p>
  31 <p class="p3"><span class="s3"><b>Inherits from: </b><a href="../../Core/Object.html"><span class="s4"><b>Object</b></span></a></span><b> : </b><a href="../../Core/Kernel/AbstractFunction.html"><b>AbstractFunction</b></a><b> : </b><a href="../UGen.html"><b>UGen</b></a><b> :<span class="Apple-converted-space"> </span></b><span class="s3"> <b>InfoUGenBase</b></span></p>
  32 <p class="p4"><br></p>
  33 <p class="p1"><b>SubsampleOffset.ir</b></p>
  34 <p class="p4"><br></p>
  35 <p class="p4"><br></p>
  36 <p class="p1">When a synth is created from a time stamped osc-bundle, it starts calculation at the next possible block (normally 64 samples). Using an <b>OffsetOut</b> ugen, one can delay the audio so that it matches sample accurately.<span class="Apple-converted-space"> </span></p>
  37 <p class="p1">For some synthesis methods, one needs subsample accuracy. <b>SubsampleOffset</b> provides the information where, within the current sample, the synth was scheduled. It can be used to offset envelopes or resample the audio output.</p>
  38 <p class="p4"><br></p>
  39 <p class="p1">see also: <a href="../InOut/OffsetOut.html"><span class="s5">OffsetOut</span></a></p>
  40 <p class="p4"><br></p>
  41 <p class="p4"><br></p>
  42 <p class="p2"><br></p>
  43 <p class="p5">// example: demonstrate cubic subsample interpolation</p>
  44 <p class="p2"><br></p>
  45 <p class="p2"><br></p>
  46 <p class="p5"><span class="s5">Server</span><span class="s3">.default = s = </span><span class="s5">Server</span><span class="s3">.internal; </span>// switch servers for scope</p>
  47 <p class="p2"><br></p>
  48 <p class="p2"><br></p>
  49 <p class="p5">// impulse train that can be moved between samples</p>
  50 <p class="p6">(</p>
  51 <p class="p7">SynthDef<span class="s3">(</span><span class="s6">\Help_SubsampleOffset</span><span class="s3">, { </span>|out, addOffset|</p>
  52 <p class="p6"><span class="Apple-tab-span">     </span><span class="s5">var</span> in, dt, sampDur, extraSamples, sampleOffset, resampledSignal;</p>
  53 <p class="p6"><span class="Apple-tab-span">     </span>in = <span class="s5">Impulse</span>.ar(2000, 0, 0.3); <span class="s7">// some input.</span></p>
  54 <p class="p5"><span class="s3"><span class="Apple-tab-span">    </span>sampDur = </span><span class="s5">SampleDur</span><span class="s3">.ir; <span class="Apple-tab-span">    </span></span>// duration of one sample</p>
  55 <p class="p5"><span class="s3"><span class="Apple-tab-span">    </span>extraSamples = 4;<span class="Apple-tab-span">   </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span></span>// DelayC needs at least 4 samples buffer</p>
  56 <p class="p5"><span class="s3"><span class="Apple-tab-span">    </span>sampleOffset = 1 - </span><span class="s5">SubsampleOffset</span><span class="s3">.ir; </span>// balance out subsample offset</p>
  57 <p class="p6"><span class="Apple-tab-span">     </span>sampleOffset = sampleOffset + <span class="s5">MouseX</span>.kr(0, addOffset); <span class="s7">// add a mouse dependent offset</span></p>
  58 <p class="p5"><span class="s3"><span class="Apple-tab-span">    </span></span>// cubic resampling:</p>
  59 <p class="p6"><span class="Apple-tab-span">     </span>resampledSignal = <span class="s5">DelayC</span>.ar(in,<span class="Apple-converted-space"> </span></p>
  60 <p class="p6"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span>maxdelaytime: sampDur * (1 + extraSamples),</p>
  61 <p class="p6"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span>delaytime: sampDur * (sampleOffset + extraSamples)</p>
  62 <p class="p6"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span>);</p>
  63 <p class="p6"><span class="Apple-tab-span">     </span><span class="s5">OffsetOut</span>.ar(out, resampledSignal)</p>
  64 <p class="p6">}).send(s);</p>
  65 <p class="p6">)</p>
  66 <p class="p2"><br></p>
  67 <p class="p5">// create 2 pulse trains 1 sample apart, move one relatively to the other.</p>
  68 <p class="p5">// when cursor is at the left, the impulses are adjacent, on the right, they are</p>
  69 <p class="p5">// exactly 1 sample apart.</p>
  70 <p class="p2"><br></p>
  71 <p class="p6">(</p>
  72 <p class="p6"><span class="s5">var</span> dt = s.sampleRate.reciprocal; <span class="s7">// 1 sample delay</span></p>
  73 <p class="p6">s.sendBundle(0.2, [9, <span class="s6">\Help_SubsampleOffset</span>, s.nextNodeID, 1, 1, <span class="s6">\out</span>, 40, <span class="s6">\addOffset</span>, 3]);</p>
  74 <p class="p6">s.sendBundle(0.2 + dt, [9, <span class="s6">\Help_SubsampleOffset</span>, s.nextNodeID, 1, 1, <span class="s6">\out</span>, 40, <span class="s6">\addOffset</span>, 0]);</p>
  75 <p class="p6">)</p>
  76 <p class="p2"><br></p>
  77 <p class="p6">s.scope(1, 40, zoom: 0.2);</p>
  78 <p class="p2"><br></p>
  79 <p class="p2"><br></p>
  80 <p class="p2"><br></p>
  81 <p class="p2"><br></p>
  82 <p class="p2"><br></p>
  83 <p class="p5">// example of a subsample accurate sine grain:</p>
  84 <p class="p5">// (I don't hear a difference to normal sample accurate grains, but maybe</p>
  85 <p class="p5">// someone could add an example that shows the effect)</p>
  86 <p class="p2"><br></p>
  87 <p class="p6">(</p>
  88 <p class="p8"><span class="s5">SynthDef</span><span class="s3">(</span>\Help_Subsample_Grain<span class="s3">,<span class="Apple-converted-space"> </span></span></p>
  89 <p class="p6"><span class="Apple-tab-span">     </span>{ <span class="s5">arg</span> out=0, freq=440, sustain=0.005, attack=0.001;</p>
  90 <p class="p6"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="s5">var</span> env, offset, sig, sd;</p>
  91 <p class="p2"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span></p>
  92 <p class="p6"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span>sd = <span class="s5">SampleDur</span>.ir;</p>
  93 <p class="p6"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span>offset = (1 - <span class="s5">SubsampleOffset</span>.ir) * sd;</p>
  94 <p class="p5"><span class="s3"><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span></span>// free synth after delay:</p>
  95 <p class="p6"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="s5">Line</span>.ar(1,0, attack + sustain + offset, doneAction:2); <span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span>env = <span class="s5">EnvGen</span>.kr(<span class="s5">Env</span>.perc(attack, sustain, 0.2));</p>
  96 <p class="p6"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span>sig = <span class="s5">SinOsc</span>.ar(freq, 0, env);</p>
  97 <p class="p2"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span></p>
  98 <p class="p6"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span>sig = <span class="s5">DelayC</span>.ar(sig, sd * 4, offset);</p>
  99 <p class="p6"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="s5">OffsetOut</span>.ar(out, sig);</p>
 100 <p class="p6"><span class="Apple-tab-span">     </span>}, [<span class="s6">\ir</span>, <span class="s6">\ir</span>, <span class="s6">\ir</span>, <span class="s6">\ir</span>]).send(s);</p>
 101 <p class="p6">)</p>
 102 <p class="p2"><br></p>
 103 <p class="p6">(</p>
 104 <p class="p7"><span class="s3"><span class="Apple-tab-span">    </span></span>Routine<span class="s3"> {</span></p>
 105 <p class="p6"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span>loop {</p>
 106 <p class="p6"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span>s.sendBundle(0.2, [9, <span class="s6">\Help_Subsample_Grain</span>, -1, 1, 1, <span class="s6">\freq</span>, 1000]);</p>
 107 <p class="p6"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span><span class="Apple-tab-span">    </span>rrand(0.001, 0.002).wait;</p>
 108 <p class="p6"><span class="Apple-tab-span">     </span><span class="Apple-tab-span">    </span>}</p>
 109 <p class="p6"><span class="Apple-tab-span">     </span>}.play;</p>
 110 <p class="p6">)</p>
 111 <p class="p2"><br></p>
 112 <p class="p2"><br></p>
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