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<h2>
<span class="refentrytitle">pvsmooth</span>
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<p>pvsmooth —
Smooth the amplitude and frequency time functions of a pv stream using parallel 1st order
lowpass IIR filters with time-varying cutoff frequency.
</p>
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<div class="refsect1" title="Description">
<a id="id3140820"></a>
<h2>Description</h2>
<p>
Smooth the amplitude and frequency time functions of a pv stream using a 1st order
lowpass IIR with time-varying cutoff frequency. This opcode uses the same filter
as the 'tone' opcode, but this time acting separately on the amplitude and frequency
time functions that make up a pv stream. The cutoff frequency parameter runs at the
control-rate, but unlike tone and tonek, it is not specified in Hz, but as fractions
of 1/2 frame-rate (actually the pv stream sampling rate), which is easier to
understand. This means that the highest cutoff frequency is 1 and the lowest 0; the lower
the frequency the smoother the functions and more pronounced the effect will be. This
opcode produces effects that are more or less similar to pvsblur, but with two important
differences: 1.smoothing of amplitudes and frequencies use separate sets of filters; and 2. there is
no increase in computational cost when higher amounts of 'blurring' (smoothing) are desired.
</p>
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<div class="refsect1" title="Syntax">
<a id="id3140830"></a>
<h2>Syntax</h2>
<pre class="synopsis">fsig <span class="command"><strong>pvsmooth</strong></span> fsigin, kacf, kfcf</pre>
</div>
<div class="refsect1" title="Performance">
<a id="id3140588"></a>
<h2>Performance</h2>
<p>
<span class="emphasis"><em>fsig</em></span> -- output pv stream
</p>
<p>
<span class="emphasis"><em>fsigin</em></span> -- input pv stream.
</p>
<p>
<span class="emphasis"><em>kacf</em></span> -- amount of cutoff frequency for amplitude function filtering, between 0 and 1,
in fractions of 1/2 frame-rate.
</p>
<p>
<span class="emphasis"><em>kfcf</em></span> -- amount of cutoff frequency for frequency function filtering, between 0 and 1,
in fractions of 1/2 frame-rate.
</p>
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<th align="left">Warning</th>
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<td align="left" valign="top">
<p>
It is unsafe to use the same f-variable for both input and output of pvs opcodes. Using the same one might lead to undefined behavior on some opcodes. Use a different one on the left and right sides of the opcode.
</p>
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<div class="refsect1" title="Examples">
<a id="id3141498"></a>
<h2>Examples</h2>
<p>
</p>
<div class="example">
<a id="id3141506"></a>
<p class="title">
<b>Example 491. Example</b>
</p>
<div class="example-contents">
<pre class="programlisting">
asig1 in ; input
fim pvsanal asig1,1024,256,1024,0 ; pvoc analysis
fou pvsmooth fim, 0.01, 0.01 ; smooth with cf at 1% of 1/2 frame-rate (ca 8.6 Hz)
aout pvsynth fou ; pvoc synthesis
</pre>
</div>
</div>
<p><br class="example-break" />
</p>
<p>
In the example above the input signal will be smoothed/blurred by pvsmooth with
a cutoff frequency of 1% of 1/2 frame-rate (which is about 172Hz, so the cf is about 8.6Hz) .</p>
</div>
<div class="refsect1" title="Credits">
<a id="id3141531"></a>
<h2>Credits</h2>
<p>
</p>
<table border="0" summary="Simple list" class="simplelist">
<tr>
<td>Author: Victor Lazzarini</td>
</tr>
<tr>
<td>May 2006 </td>
</tr>
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<p>
</p>
<p>New plugin in version 5</p>
<p>May 2006.</p>
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