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<h1>libaudiomask - Simultaneous audio mask threshold estimation library </h1><h3 class="version">1.0 </h3><dl class="author"><dt><b>Authors:</b></dt><dd>Dr Matt R. Flax <flatmax@></dd></dl>
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<img src="masking.example.jpg" alt="masking.example.jpg"/>
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<h2><a class="anchor" id="docs">
Academic</a></h2>
<p>This code also implements the roex auditory filters.</p>
<p>Please read the article located on the debian file system <a href="file:///usr/shar/doc/libaudiomask-1.0/Flax.2000.Improved.Auditory.Masking.Models.pdf">file:///usr/shar/doc/libaudiomask-1.0/Flax.2000.Improved.Auditory.Masking.Models.pdf</a></p>
<p>It may also be found on the web <a href="http://www.assta.org/sst/SST-00/cache/SST-00-Chapter9-p2.pdf">http://www.assta.org/sst/SST-00/cache/SST-00-Chapter9-p2.pdf</a> </p>
<h2><a class="anchor" id="intro">
Introduction</a></h2>
<p>This example shows how to use Dr M.R. Flax's (2000) hybrid simultaneous audio masking class to find the masking threshold of a time domain signal.</p>
<p>The compilation of this file is demonstrated in Makefile. Run this file : ./AudioMaskerExample View the results of this file using www.octave.org by running the script view.m</p>
<ul>
<li>simply type view once octave has started and you are in the suitable directory.</li>
</ul>
<p>The input audio should be stored in the file INPUTFILENAME in text format - each sample seperated by a white space.</p>
<p>========================= HOWTO =============================== </p>
<div class="fragment"><pre class="fragment"> <span class="comment">// First find the masking threshold</span>
<a class="code" href="classAudioMasker.html">AudioMasker</a> masker(sampleFreq, count); <span class="comment">// Create the audio masker class using fs=sampleFreq and count filters</span>
masker.excite(input, sampleCount); <span class="comment">// find the mask for the array of input data which has sampleCount time samples.</span>
<span class="comment">// Now do something with the masking threshold ...</span>
<span class="comment">// The frequency domain mask is now located here</span>
<span class="keywordflow">for</span> (<span class="keywordtype">int</span> j=0; j<count;j++)
masker.mask[j]; <span class="comment">// This is the mask at each of the count frequencies of interest</span>
<span class="comment">// A more sophisticated example - find the threshold for each Fourier bin</span>
<span class="keywordtype">double</span> fact=(<span class="keywordtype">double</span>)sampleFreq/((double)sampleCount-1.0); <span class="comment">// convert from an index to the equivalent * Fourier bin frequency</span>
<span class="keywordflow">for</span> (<span class="keywordtype">int</span> j=0; j<halfSampleCount;j++){
cout<<<span class="stringliteral">"finding for freq "</span><<j*fact<<<span class="charliteral">'\t'</span>; <span class="comment">// The frequency we are inspecting</span>
<span class="keywordtype">double</span> threshold=masker.findThreshold(j*fact); <span class="comment">// The masking threshold</span>
20*log10(threshold); <span class="comment">// The threshold in decibels (dB)</span>
}
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