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--></style></head><body lang="EN-US" link="blue" vlink="purple"><div class="WordSection1"><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Hi,</span></p><p class="MsoNormal">
<span style="font-size:10.0pt;font-family:"Arial","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">I am just starting up on SPEEX AEC algorithm and have couple of questions around echo cancelation algorithm used in SPEEX. </span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""> </span></p><p class="MsoListParagraph" style><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><span style>1)<span style="font:7.0pt "Times New Roman""> </span></span></span><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Usually Echo Cancelation Algorithm has support for number of components –</span></p>
<p class="MsoListParagraph" style="margin-left:1.5in;text-autospace:none"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><span style>-<span style="font:7.0pt "Times New Roman""> </span></span></span><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Non-Linear Processor (NLP)</span></p>
<p class="MsoListParagraph" style="margin-left:1.5in;text-autospace:none"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><span style>-<span style="font:7.0pt "Times New Roman""> </span></span></span><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Automatic Microphone Gain Control (AGC)</span></p>
<p class="MsoListParagraph" style="margin-left:1.5in;text-autospace:none"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><span style>-<span style="font:7.0pt "Times New Roman""> </span></span></span><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Transducer Equalization (EQ)</span></p>
<p class="MsoListParagraph" style="margin-left:1.5in;text-autospace:none"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><span style>-<span style="font:7.0pt "Times New Roman""> </span></span></span><span style="font-size:10.0pt;font-family:"Arial","sans-serif""> Dynamic Range Compression (DRC)</span></p>
<p class="MsoListParagraph" style="margin-left:1.5in;text-autospace:none"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><span style>-<span style="font:7.0pt "Times New Roman""> </span></span></span><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Ambient Noise Reduction (ANR)</span></p>
<p class="MsoListParagraph" style="margin-left:1.5in;text-autospace:none"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><span style>-<span style="font:7.0pt "Times New Roman""> </span></span></span><span style="font-size:10.0pt;font-family:"Arial","sans-serif""> Bi-directional Comfort Noise Generator (CNG)</span></p>
<p class="MsoListParagraph" style="margin-left:1.5in;text-autospace:none"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><span style>-<span style="font:7.0pt "Times New Roman""> </span></span></span><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Double-talk/Coherence/Howling detection</span></p>
<p class="MsoListParagraph" style="margin-left:1.0in;text-autospace:none"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">My question is whether the algorithm supports all the above functionalities ? Looking at speex_preprocess.h file, I find there are controls available for AGC, Noise Suppression, Echo Suppression during single talk and double talk but not clear if there are more options available. </span></p>
<p class="MsoListParagraph" style="text-autospace:none"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><span style>2)<span style="font:7.0pt "Times New Roman""> </span></span></span><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">From tuning standpoint, are there references available on how we can tune SPEEX AEC algorithm to our needs ?</span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""> </span></p><p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Thanks in advance.</span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""> </span></p><p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Prateek </span></p>
<p class="MsoNormal"> </p></div></body></html>