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<h2>
<span class="refentrytitle">pvsdemix</span>
</h2>
<p>pvsdemix —
Spectral azimuth-based de-mixing of stereo sources.
</p>
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<div class="refsect1" title="Description">
<a id="id3131883"></a>
<h2>Description</h2>
<p>
Spectral azimuth-based de-mixing of stereo sources, with a reverse-panning result. This
opcode implements the Azimuth Discrimination and Resynthesis (ADRess) algorithm, developed by
Dan Barry (Barry et Al. "Sound Source Separation Azimuth Discrimination and Resynthesis". DAFx'04,
Univ. of Napoli). The source separation, or de-mixing, is controlled by two parameters: an azimuth
position (kpos) and a subspace width (kwidth). The first one is used to locate the spectral peaks of
individual sources on a stereo mix, whereas the second widens the 'search space', including/exclufing
the peaks around kpos. These two parameters can be used interactively to extract source sounds from
a stereo mix. The algorithm is particularly successful with studio recordings where individual instruments
occupy individual panning positions; it is, in fact, a reverse-panning algorithm.
</p>
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<th align="left">Warning</th>
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<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.
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<div class="refsect1" title="Syntax">
<a id="id3132114"></a>
<h2>Syntax</h2>
<pre class="synopsis">fsig <span class="command"><strong>pvsdemix</strong></span> fleft, fright, kpos, kwidth, ipoints</pre>
</div>
<div class="refsect1" title="Performance">
<a id="id3132132"></a>
<h2>Performance</h2>
<p>
<span class="emphasis"><em>fsig</em></span> -- output pv stream
</p>
<p>
<span class="emphasis"><em>fleft</em></span> -- left channel input pv stream.
</p>
<p>
<span class="emphasis"><em>fright</em></span> -- right channel pv stream.
</p>
<p>
<span class="emphasis"><em>kpos</em></span> -- the azimuth target centre position, which will be de-mixed, from
left to right (-1 <= kpos <= 1). This is the reverse pan-pot control.
</p>
<p>
<span class="emphasis"><em>kwidth</em></span> -- the azimuth subspace width, which will determine the number
of points around kpos which will be used in the de-mixing process.
(1 <= kwidth <= ipoints)
</p>
<p>
<span class="emphasis"><em>ipoints</em></span> -- total number of discrete points, which will divide
each pan side of the stereo image. This ultimately affects
the resolution of the process.
</p>
</div>
<div class="refsect1" title="Examples">
<a id="id3132825"></a>
<h2>Examples</h2>
<p>
The example below takes a stereo input and passes through a de-mixing
process revealing a source located at ipos +/- iwidth points. These parameters
can be controlled in realtime (e.g. using FLTK widgets or MIDI) for an interactive
search of sound sources.
</p>
<div class="example">
<a id="id3132838"></a>
<p class="title">
<b>Example 474. Example</b>
</p>
<div class="example-contents">
<pre class="programlisting">
ifftsize = 1024
iwtype = 1 /* cleaner with hanning window */
ipos = -0.8 /* to the left of the stereo image */
iwidth = 20 /* use peaks of 20 points around it */
al,ar soundin "sinput.wav"
flc pvsanal al, ifftsize, ifftsize/4, ifftsize, iwtype
frc pvsanal ar, ifftsize, ifftsize/4, ifftsize, iwtype
fdm pvsdemix flc, frc, kpos, kwidth, 100
adm pvsynth fdm
outs adm,adm
</pre>
</div>
</div>
<p><br class="example-break" />
</p>
</div>
<div class="refsect1" title="Credits">
<a id="id3132859"></a>
<h2>Credits</h2>
<p>
</p>
<table border="0" summary="Simple list" class="simplelist">
<tr>
<td>Author: Victor Lazzarini</td>
</tr>
<tr>
<td>January 2005</td>
</tr>
</table>
<p>
</p>
<p>New plugin in version 5</p>
<p>January 2005.</p>
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