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14<h1 align="left">Utility Function</h1>
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16<h2>Overview</h2>
17
18<p>The following utility functions have been prepared in the AX library.</p>
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20<ul>
21<li>Function for calculating the low-pass filter coefficient.
22<li>Function for creating custom compressor tables.
23<li>Function for converting 16-bit PCM to DSP-ADPCM.
24</ul>
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26<H2>Calculating the Low-Pass Filter Coefficient</H2>
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28<p>The <a href="AXGetLpfCoefs.html"><code>AXGetLpfCoefs</code></a> function has been prepared for calculating the low-pass filter coefficient to be set in the  <a href="../Parameter_Blocks/AXPBLPF_lpf.html"><code>AXPBLPF</code></a> structure as specified using the <a href="../Voice_Parameters/AXSetVoiceLpf.html"><code>AXSetVoiceLpf</code></a> or <a href="../Voice_Parameters/AXSetVoiceLpfCoefs.html"><code>AXSetVoiceLpfCoefs</code></a> function.</p>
29
30<p>A detailed description of the low-pass filter coefficient is included in the description of the <a href="../Parameter_Blocks/AXPBLPF_lpf.html"><code>AXPBLPF</code></a> structure.</p>
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32<H2>Creating a Custom Compressor Table</H2>
33
34<p>The audio DSP compressor automatically applies an envelope to data to prevent noise when audio data in the mixing buffer exceeds the range of <code>s16</code>. A compressor table in the AX library defines the shape of this envelope.</p>
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36<p>A custom compressor table of original shape can be created using the <a href="AXMakeCompressorTable.html"><code>AXMakeCompressorTable</code></a> function.</p>
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38<p>The custom table created using the <a href="AXMakeCompressorTable.html"><code>AXMakeCompressorTable</code></a> function is registered in the AX library using the <a href="../Initialization/AXSetCompressorTable.html"><code>AXSetCompressorTable</code></a> function.</p>
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40<H2>Converting from 16-bit PCM to DSP-ADPCM</H2>
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42<p>The <a href="AXGetAdpcmData.html"><code>AXGetAdpcmData</code></a> function has been prepared so that the Wii can perform run-time conversion of 16-bit PCM data into ADPCM format for DSP (DSP-ADPCM).</p>
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44<h2>Revision History</h2>
45<P>
462008/02/25 Added information on creating compressor tables and functions related to DSP-ADPCM conversion.<br>2007/10/02 Revised the entire document following changes to the structure of the function reference.<br>2006/XX/XX Initial version.<br>
47</P>
48
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