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<h2>
<span class="refentrytitle">vbap4</span>
</h2>
<p>vbap4 —
Distributes an audio signal among 4 channels.
</p>
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<div class="refsect1" title="Description">
<a id="idp50459832"></a>
<h2>Description</h2>
<p>
Distributes an audio signal among 4 channels.
</p>
</div>
<div class="refsect1" title="Syntax">
<a id="idp50460488"></a>
<h2>Syntax</h2>
<pre class="synopsis">ar1, ar2, ar3, ar4 <span class="command"><strong>vbap4</strong></span> asig, kazim [, kelev] [, kspread]</pre>
</div>
<div class="refsect1" title="Performance">
<a id="idp50464232"></a>
<h2>Performance</h2>
<p>
<span class="emphasis"><em>asig</em></span> -- audio signal to be panned
</p>
<p>
<span class="emphasis"><em>kazim</em></span> -- azimuth angle of the virtual source
</p>
<p>
<span class="emphasis"><em>kelev</em></span> (optional) -- elevation angle of the virtual source
</p>
<p>
<span class="emphasis"><em>kspread</em></span> (optional) -- spreading of the virtual source (range 0 - 100). If value is zero, conventional amplitude panning is used. When <span class="emphasis"><em>kspread</em></span> is increased, the number of loudspeakers used in panning increases. If value is 100, the sound is applied to all loudspeakers.
</p>
<p>
<span class="emphasis"><em>vbap4</em></span> takes an input signal, <span class="emphasis"><em>asig</em></span> and distributes it among 4 outputs, according to the controls <span class="emphasis"><em>kazim</em></span> and <span class="emphasis"><em>kelev</em></span>, and the configured loudspeaker placement. If <span class="emphasis"><em>idim</em></span> = 2, <span class="emphasis"><em>kelev</em></span> is set to zero. The distribution is performed using Vector Base Amplitude Panning (VBAP - See reference). VBAP distributes the signal using loudspeaker data configured with <span class="emphasis"><em>vbaplsinit</em></span>. The signal is applied to, at most, two loudspeakers in 2-D loudspeaker configurations, and three loudspeakers in 3-D loudspeaker configurations. If the virtual source is panned outside the region spanned by loudspeakers, the nearest loudspeakers are used in panning.
</p>
<div class="warning" title="Warning" style="margin-left: 0.5in; margin-right: 0.5in;">
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<th align="left">Warning</th>
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<td align="left" valign="top">
<p>Please note that all <span class="emphasis"><em>vbap</em></span> panning opcodes require the <span class="emphasis"><em>vbap</em></span> system to be initialized using <a class="link" href="vbaplsinit.html" title="vbaplsinit"><em class="citetitle">vbaplsinit</em></a>.</p>
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<div class="refsect1" title="Examples">
<a id="idp50522352"></a>
<h2>Examples</h2>
<p>
See the entry for <a class="link" href="vbap8.html" title="vbap8"><em class="citetitle">vbap8</em></a> for an example of usage of the <span class="emphasis"><em>vbap</em></span> opcodes.
</p>
</div>
<div class="refsect1" title="Reference">
<a id="idp50523712"></a>
<h2>Reference</h2>
<p>
Ville Pulkki: <span class="quote">“<span class="quote">Virtual Sound Source Positioning Using Vector Base Amplitude Panning</span>”</span> <span class="emphasis"><em>Journal of the Audio Engineering Society</em></span>, 1997 June, Vol. 45/6, p. 456.
</p>
</div>
<div class="refsect1" title="Examples">
<a id="idp50524896"></a>
<h2>Examples</h2>
<p>
Here is an example of the vbap4 opcode. It uses the file <a class="ulink" href="examples/vbap4.csd" target="_top"><em class="citetitle">vbap4.csd</em></a>.
</p>
<div class="example">
<a id="idp50525864"></a>
<p class="title">
<strong>Example 923. Example of the vbap4 opcode.</strong>
</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>
-odac <span class="comment">;;;realtime audio out</span>
<span class="comment">;-iadc ;;;uncomment -iadc if realtime audio input is needed too</span>
<span class="comment">; For Non-realtime ouput leave only the line below:</span>
<span class="comment">; -o vbap4.wav -W ;;; for file output any platform</span>
<span class="csdtag"></CsOptions></span>
<span class="csdtag"><CsInstruments></span>
<span class="ohdr">sr</span> <span class="op">=</span> 44100
<span class="ohdr">ksmps</span> <span class="op">=</span> 32
<span class="ohdr">nchnls</span> <span class="op">=</span> 4 <span class="comment">;quad</span>
<span class="ohdr">0dbfs</span> <span class="op">=</span> 1
<span class="opc">vbaplsinit</span> 2, 4, 0, 90, 180, 270
<span class="oblock">instr</span> 1
asig <span class="opc">diskin2</span> "beats.wav", 1, 0, 1 <span class="comment">;loop beats.wav</span>
kaz <span class="opc">line</span> 0, p3, p4 <span class="comment">;come from right rear speaker & </span>
a1,a2,a3,a4 <span class="opc">vbap4</span> asig, 180, 100, kaz <span class="comment">;change spread of soundsource</span>
<span class="opc">printks</span> "spread of source <span class="op">=</span> <span class="op">%</span>d\n", 1, kaz <span class="comment">;print spread value</span>
<span class="opc">outq</span> a1,a2,a3,a4
<span class="oblock">endin</span>
<span class="csdtag"></CsInstruments></span>
<span class="csdtag"><CsScore></span>
<span class="stamnt">i</span> 1 0 12 100
<span class="stamnt">e</span>
<span class="csdtag"></CsScore></span>
<span class="csdtag"></CsoundSynthesizer></span>
</pre>
</div>
</div>
<p><br class="example-break" />
Its output should include lines like these:
</p>
<pre class="screen">
spread of source = 0
spread of source = 8
spread of source = 17
spread of source = 25
spread of source = 33
spread of source = 42
spread of source = 50
spread of source = 58
spread of source = 67
spread of source = 75
spread of source = 83
spread of source = 92
spread of source = 100
</pre>
<p>
</p>
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<div class="refsect1" title="See Also">
<a id="idp50528816"></a>
<h2>See Also</h2>
<p>
<a class="link" href="vbap16.html" title="vbap16"><em class="citetitle">vbap16</em></a>,
<a class="link" href="vbap16move.html" title="vbap16move"><em class="citetitle">vbap16move</em></a>,
<a class="link" href="vbap4move.html" title="vbap4move"><em class="citetitle">vbap4move</em></a>,
<a class="link" href="vbap8.html" title="vbap8"><em class="citetitle">vbap8</em></a>,
<a class="link" href="vbap8move.html" title="vbap8move"><em class="citetitle">vbap8move</em></a>,
<a class="link" href="vbaplsinit.html" title="vbaplsinit"><em class="citetitle">vbaplsinit</em></a>,
<a class="link" href="vbapz.html" title="vbapz"><em class="citetitle">vbapz</em></a>,
<a class="link" href="vbapzmove.html" title="vbapzmove"><em class="citetitle">vbapzmove</em></a>
</p>
</div>
<div class="refsect1" title="Credits">
<a id="idp50533216"></a>
<h2>Credits</h2>
<p>
</p>
<table border="0" summary="Simple list" class="simplelist">
<tr>
<td>Author: Ville Pulkki</td>
</tr>
<tr>
<td>Sibelius Academy Computer Music Studio</td>
</tr>
<tr>
<td>Laboratory of Acoustics and Audio Signal Processing</td>
</tr>
<tr>
<td>Helsinki University of Technology</td>
</tr>
<tr>
<td>Helsinki, Finland</td>
</tr>
<tr>
<td>May 2000</td>
</tr>
</table>
<p>
</p>
<p>New in Csound Version 4.06. Input parameters accept k-rate since Csund 5.09.</p>
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