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<div class="refentry" title="grain">
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<h2>
<span class="refentrytitle">grain</span>
</h2>
<p>grain —
Generates granular synthesis textures.
</p>
</div>
<div class="refsect1" title="Description">
<a id="id2932686"></a>
<h2>Description</h2>
<p>
Generates granular synthesis textures.
</p>
</div>
<div class="refsect1" title="Syntax">
<a id="id2932698"></a>
<h2>Syntax</h2>
<pre class="synopsis">ares <span class="command"><strong>grain</strong></span> xamp, xpitch, xdens, kampoff, kpitchoff, kgdur, igfn, \
iwfn, imgdur [, igrnd]</pre>
</div>
<div class="refsect1" title="Initialization">
<a id="id2932719"></a>
<h2>Initialization</h2>
<p>
<span class="emphasis"><em>igfn</em></span> -- The ftable number of the grain waveform. This can be just a sine wave or a sampled sound.
</p>
<p>
<span class="emphasis"><em>iwfn</em></span> -- Ftable number of the amplitude envelope used for the grains (see also <a class="link" href="GEN20.html" title="GEN20"><em class="citetitle">GEN20</em></a>).
</p>
<p>
<span class="emphasis"><em>imgdur</em></span> -- Maximum grain duration in seconds. This is the biggest value to be assigned to <span class="emphasis"><em>kgdur</em></span>.
</p>
<p>
<span class="emphasis"><em>igrnd</em></span> (optional) -- if non-zero, turns off grain offset randomness. This means that all grains will begin reading from the beginning of the <span class="emphasis"><em>igfn</em></span> table. If zero (the default), grains will start reading from random <span class="emphasis"><em>igfn</em></span> table positions.
</p>
</div>
<div class="refsect1" title="Performance">
<a id="id2932783"></a>
<h2>Performance</h2>
<p>
<span class="emphasis"><em>xamp</em></span> -- Amplitude of each grain.
</p>
<p>
<span class="emphasis"><em>xpitch</em></span> -- Grain pitch. To use the original frequency of the input sound, use the formula:
</p>
<div class="literallayout">
<p> sndsr / ftlen(<span class="emphasis"><em>igfn</em></span>)</p>
</div>
<p>
</p>
<p>
where sndsr is the original sample rate of the <span class="emphasis"><em>igfn</em></span> sound.
</p>
<p>
<span class="emphasis"><em>xdens</em></span> -- Density of grains measured in grains per second. If this is constant then the output is synchronous granular synthesis, very similar to <a class="link" href="fof.html" title="fof"><em class="citetitle">fof</em></a>. If <span class="emphasis"><em>xdens</em></span> has a random element (like added noise), then the result is more like asynchronous granular synthesis.
</p>
<p>
<span class="emphasis"><em>kampoff</em></span> -- Maximum amplitude deviation from <span class="emphasis"><em>xamp</em></span>. This means that the maximum amplitude a grain can have is <span class="emphasis"><em>xamp</em></span> + <span class="emphasis"><em>kampoff</em></span> and the minimum is <span class="emphasis"><em>xamp</em></span>. If <span class="emphasis"><em>kampoff</em></span> is set to zero then there is no random amplitude for each grain.
</p>
<p>
<span class="emphasis"><em>kpitchoff</em></span> -- Maximum pitch deviation from <span class="emphasis"><em>xpitch</em></span> in Hz. Similar to <span class="emphasis"><em>kampoff</em></span>.
</p>
<p>
<span class="emphasis"><em>kgdur</em></span> -- Grain duration in seconds. The maximum value for this should be declared in <span class="emphasis"><em>imgdur</em></span>. If <span class="emphasis"><em>kgdur</em></span> at any point becomes greater than <span class="emphasis"><em>imgdur</em></span>, it will be truncated to <span class="emphasis"><em>imgdur</em></span>.
</p>
<p>
The grain generator is based primarily on work and writings of Barry Truax and Curtis Roads.
</p>
</div>
<div class="refsect1" title="Examples">
<a id="id2932929"></a>
<h2>Examples</h2>
<p>
This example generates a texture with gradually shorter grains and wider amp and pitch spread. It uses the file <a class="ulink" href="examples/grain.csd" target="_top"><em class="citetitle">grain.csd</em></a>, and <a class="ulink" href="examples/mary.wav" target="_top"><em class="citetitle">mary.wav</em></a>.
</p>
<div class="example">
<a id="id2932954"></a>
<p class="title">
<b>Example 289. Example of the grain opcode.</b>
</p>
<div class="example-contents">
<p>See the sections <a class="link" href="UsingRealTime.html" title="Real-Time Audio"><em class="citetitle">Real-time Audio</em></a> and <a class="link" href="CommandFlags.html" title="Csound command line"><em class="citetitle">Command Line Flags</em></a> for more information on using command line flags.</p>
<pre class="programlisting">
<span class="csdtag"><CsoundSynthesizer></span>
<span class="csdtag"><CsOptions></span>
<span class="comment">; Select audio/midi flags here according to platform</span>
<span class="comment">; Audio out Audio in No messages</span>
-odac -iadc -d <span class="comment">;;;RT audio I/O</span>
<span class="comment">; For Non-realtime ouput leave only the line below:</span>
<span class="comment">; -o grain.wav -W ;;; for file output any platform</span>
<span class="csdtag"></CsOptions></span>
<span class="csdtag"><CsInstruments></span>
<span class="comment">; Initialize the global variables.</span>
<span class="ohdr">sr</span> <span class="op">=</span> 44100
<span class="ohdr">kr</span> <span class="op">=</span> 44100
<span class="ohdr">ksmps</span> <span class="op">=</span> 1
<span class="ohdr">nchnls</span> <span class="op">=</span> 1
<span class="oblock">instr</span> 1
insnd <span class="op">=</span> 10
ibasfrq <span class="op">=</span> 44100 <span class="op">/</span> <span class="opc">ftlen</span>(insnd) <span class="comment">; Use original sample rate of insnd file</span>
kamp <span class="opc">expseg</span> 220, p3<span class="op">/</span>2, 600, p3<span class="op">/</span>2, 220
kpitch <span class="opc">line</span> ibasfrq, p3, ibasfrq <span class="op">*</span> .8
kdens <span class="opc">line</span> 600, p3, 200
kaoff <span class="opc">line</span> 0, p3, 5000
kpoff <span class="opc">line</span> 0, p3, ibasfrq <span class="op">*</span> .5
kgdur <span class="opc">line</span> .4, p3, .1
imaxgdur <span class="op">=</span> .5
ar <span class="opc">grain</span> kamp, kpitch, kdens, kaoff, kpoff, kgdur, insnd, 5, imaxgdur, 0.0
<span class="opc">out</span> ar
<span class="oblock">endin</span>
<span class="csdtag"></CsInstruments></span>
<span class="csdtag"><CsScore></span>
<span class="stamnt">f</span>5 0 512 20 2 <span class="comment">; Hanning window</span>
<span class="stamnt">f</span>10 0 262144 1 "mary.wav" 0 0 0
<span class="stamnt">i</span>1 0 6
<span class="stamnt">e</span>
<span class="csdtag"></CsScore></span>
<span class="csdtag"></CsoundSynthesizer></span>
</pre>
</div>
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<p><br class="example-break" />
</p>
</div>
<div class="refsect1" title="Credits">
<a id="id2932992"></a>
<h2>Credits</h2>
<p>
</p>
<table border="0" summary="Simple list" class="simplelist">
<tr>
<td>Author: Paris Smaragdis</td>
</tr>
<tr>
<td>MIT</td>
</tr>
<tr>
<td>May 1997</td>
</tr>
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