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<h1>src/libsphinxbase/feat/agc.c</h1> </div>
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<div class="contents">
<div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">/* -*- c-basic-offset: 4; indent-tabs-mode: nil -*- */</span>
<a name="l00002"></a>00002 <span class="comment">/* ====================================================================</span>
<a name="l00003"></a>00003 <span class="comment"> * Copyright (c) 1999-2004 Carnegie Mellon University. All rights</span>
<a name="l00004"></a>00004 <span class="comment"> * reserved.</span>
<a name="l00005"></a>00005 <span class="comment"> *</span>
<a name="l00006"></a>00006 <span class="comment"> * Redistribution and use in source and binary forms, with or without</span>
<a name="l00007"></a>00007 <span class="comment"> * modification, are permitted provided that the following conditions</span>
<a name="l00008"></a>00008 <span class="comment"> * are met:</span>
<a name="l00009"></a>00009 <span class="comment"> *</span>
<a name="l00010"></a>00010 <span class="comment"> * 1. Redistributions of source code must retain the above copyright</span>
<a name="l00011"></a>00011 <span class="comment"> * notice, this list of conditions and the following disclaimer. </span>
<a name="l00012"></a>00012 <span class="comment"> *</span>
<a name="l00013"></a>00013 <span class="comment"> * 2. Redistributions in binary form must reproduce the above copyright</span>
<a name="l00014"></a>00014 <span class="comment"> * notice, this list of conditions and the following disclaimer in</span>
<a name="l00015"></a>00015 <span class="comment"> * the documentation and/or other materials provided with the</span>
<a name="l00016"></a>00016 <span class="comment"> * distribution.</span>
<a name="l00017"></a>00017 <span class="comment"> *</span>
<a name="l00018"></a>00018 <span class="comment"> * This work was supported in part by funding from the Defense Advanced </span>
<a name="l00019"></a>00019 <span class="comment"> * Research Projects Agency and the National Science Foundation of the </span>
<a name="l00020"></a>00020 <span class="comment"> * United States of America, and the CMU Sphinx Speech Consortium.</span>
<a name="l00021"></a>00021 <span class="comment"> *</span>
<a name="l00022"></a>00022 <span class="comment"> * THIS SOFTWARE IS PROVIDED BY CARNEGIE MELLON UNIVERSITY ``AS IS'' AND </span>
<a name="l00023"></a>00023 <span class="comment"> * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, </span>
<a name="l00024"></a>00024 <span class="comment"> * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR</span>
<a name="l00025"></a>00025 <span class="comment"> * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY</span>
<a name="l00026"></a>00026 <span class="comment"> * NOR ITS EMPLOYEES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,</span>
<a name="l00027"></a>00027 <span class="comment"> * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT </span>
<a name="l00028"></a>00028 <span class="comment"> * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, </span>
<a name="l00029"></a>00029 <span class="comment"> * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY </span>
<a name="l00030"></a>00030 <span class="comment"> * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT </span>
<a name="l00031"></a>00031 <span class="comment"> * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE </span>
<a name="l00032"></a>00032 <span class="comment"> * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.</span>
<a name="l00033"></a>00033 <span class="comment"> *</span>
<a name="l00034"></a>00034 <span class="comment"> * ====================================================================</span>
<a name="l00035"></a>00035 <span class="comment"> *</span>
<a name="l00036"></a>00036 <span class="comment"> */</span>
<a name="l00037"></a>00037 <span class="comment">/*</span>
<a name="l00038"></a>00038 <span class="comment"> * agc.c -- Various forms of automatic gain control (AGC)</span>
<a name="l00039"></a>00039 <span class="comment"> * </span>
<a name="l00040"></a>00040 <span class="comment"> * **********************************************</span>
<a name="l00041"></a>00041 <span class="comment"> * CMU ARPA Speech Project</span>
<a name="l00042"></a>00042 <span class="comment"> *</span>
<a name="l00043"></a>00043 <span class="comment"> * Copyright (c) 1996 Carnegie Mellon University.</span>
<a name="l00044"></a>00044 <span class="comment"> * ALL RIGHTS RESERVED.</span>
<a name="l00045"></a>00045 <span class="comment"> * **********************************************</span>
<a name="l00046"></a>00046 <span class="comment"> * </span>
<a name="l00047"></a>00047 <span class="comment"> * HISTORY</span>
<a name="l00048"></a>00048 <span class="comment"> * $Log$</span>
<a name="l00049"></a>00049 <span class="comment"> * Revision 1.5 2005/06/21 19:25:41 arthchan2003</span>
<a name="l00050"></a>00050 <span class="comment"> * 1, Fixed doxygen documentation. 2, Added $ keyword.</span>
<a name="l00051"></a>00051 <span class="comment"> * </span>
<a name="l00052"></a>00052 <span class="comment"> * Revision 1.3 2005/03/30 01:22:46 archan</span>
<a name="l00053"></a>00053 <span class="comment"> * Fixed mistakes in last updates. Add</span>
<a name="l00054"></a>00054 <span class="comment"> *</span>
<a name="l00055"></a>00055 <span class="comment"> * </span>
<a name="l00056"></a>00056 <span class="comment"> * 04-Nov-95 M K Ravishankar (rkm@cs.cmu.edu) at Carnegie Mellon University</span>
<a name="l00057"></a>00057 <span class="comment"> * Created.</span>
<a name="l00058"></a>00058 <span class="comment"> */</span>
<a name="l00059"></a>00059
<a name="l00060"></a>00060 <span class="preprocessor">#include <string.h></span>
<a name="l00061"></a>00061 <span class="preprocessor">#ifdef HAVE_CONFIG_H</span>
<a name="l00062"></a>00062 <span class="preprocessor"></span><span class="preprocessor">#include <config.h></span>
<a name="l00063"></a>00063 <span class="preprocessor">#endif</span>
<a name="l00064"></a>00064 <span class="preprocessor"></span>
<a name="l00065"></a>00065 <span class="preprocessor">#include "sphinxbase/err.h"</span>
<a name="l00066"></a>00066 <span class="preprocessor">#include "sphinxbase/ckd_alloc.h"</span>
<a name="l00067"></a>00067 <span class="preprocessor">#include "sphinxbase/agc.h"</span>
<a name="l00068"></a>00068
<a name="l00069"></a>00069 <span class="comment">/* NOTE! These must match the enum in agc.h */</span>
<a name="l00070"></a><a class="code" href="agc_8h.html#a6ea1b2b3d482cf08eb36084629503c80">00070</a> <span class="keyword">const</span> <span class="keywordtype">char</span> *<a class="code" href="agc_8h.html#a6ea1b2b3d482cf08eb36084629503c80" title="String representations of agc_type_t values.">agc_type_str</a>[] = {
<a name="l00071"></a>00071 <span class="stringliteral">"none"</span>,
<a name="l00072"></a>00072 <span class="stringliteral">"max"</span>,
<a name="l00073"></a>00073 <span class="stringliteral">"emax"</span>,
<a name="l00074"></a>00074 <span class="stringliteral">"noise"</span>
<a name="l00075"></a>00075 };
<a name="l00076"></a>00076 <span class="keyword">static</span> <span class="keyword">const</span> <span class="keywordtype">int</span> n_agc_type_str = <span class="keyword">sizeof</span>(<a class="code" href="agc_8h.html#a6ea1b2b3d482cf08eb36084629503c80" title="String representations of agc_type_t values.">agc_type_str</a>)/<span class="keyword">sizeof</span>(agc_type_str[0]);
<a name="l00077"></a>00077
<a name="l00078"></a>00078 <a class="code" href="agc_8h.html#a5524df49e0425cc6b1c002bc704a8103" title="Types of acoustic gain control to apply to the features.">agc_type_t</a>
<a name="l00079"></a><a class="code" href="agc_8h.html#aebd0689591488378192e13f6d2646bc1">00079</a> <a class="code" href="agc_8h.html#aebd0689591488378192e13f6d2646bc1" title="Convert string representation (from command-line) to agc_type_t.">agc_type_from_str</a>(<span class="keyword">const</span> <span class="keywordtype">char</span> *str)
<a name="l00080"></a>00080 {
<a name="l00081"></a>00081 <span class="keywordtype">int</span> i;
<a name="l00082"></a>00082
<a name="l00083"></a>00083 <span class="keywordflow">for</span> (i = 0; i < n_agc_type_str; ++i) {
<a name="l00084"></a>00084 <span class="keywordflow">if</span> (0 == strcmp(str, <a class="code" href="agc_8h.html#a6ea1b2b3d482cf08eb36084629503c80" title="String representations of agc_type_t values.">agc_type_str</a>[i]))
<a name="l00085"></a>00085 <span class="keywordflow">return</span> (<a class="code" href="agc_8h.html#a5524df49e0425cc6b1c002bc704a8103" title="Types of acoustic gain control to apply to the features.">agc_type_t</a>)i;
<a name="l00086"></a>00086 }
<a name="l00087"></a>00087 <a class="code" href="err_8h.html#a1a4495946ab2449d61108fe829a94613" title="Exit with non-zero status after error message.">E_FATAL</a>(<span class="stringliteral">"Unknown AGC type '%s'\n"</span>, str);
<a name="l00088"></a>00088 <span class="keywordflow">return</span> AGC_NONE;
<a name="l00089"></a>00089 }
<a name="l00090"></a>00090
<a name="l00091"></a><a class="code" href="agc_8h.html#a5c7ee7b19f8dcfd0c28b4dc76a283dc7">00091</a> <a class="code" href="structagc__s.html" title="Structure holding data for doing AGC.">agc_t</a> *<a class="code" href="agc_8h.html#a5c7ee7b19f8dcfd0c28b4dc76a283dc7" title="Initialize AGC structure with default values.">agc_init</a>(<span class="keywordtype">void</span>)
<a name="l00092"></a>00092 {
<a name="l00093"></a>00093 <a class="code" href="structagc__s.html" title="Structure holding data for doing AGC.">agc_t</a> *agc;
<a name="l00094"></a>00094 agc = <a class="code" href="ckd__alloc_8h.html#aa00ef21903bc4f8a972488417adc8d2e" title="Macros to simplify the use of above functions.">ckd_calloc</a>(1, <span class="keyword">sizeof</span>(*agc));
<a name="l00095"></a>00095 agc-><a class="code" href="structagc__s.html#a4c896e65da00c79b77b23272474fcffc" title="Noise threshold (for AGC_NOISE only)">noise_thresh</a> = FLOAT2MFCC(2.0);
<a name="l00096"></a>00096
<a name="l00097"></a>00097 <span class="keywordflow">return</span> agc;
<a name="l00098"></a>00098 }
<a name="l00099"></a>00099
<a name="l00100"></a><a class="code" href="agc_8h.html#a6a050fc4b079be05b1946636d5d7f3aa">00100</a> <span class="keywordtype">void</span> <a class="code" href="agc_8h.html#a6a050fc4b079be05b1946636d5d7f3aa" title="Free AGC structure.">agc_free</a>(<a class="code" href="structagc__s.html" title="Structure holding data for doing AGC.">agc_t</a> *agc)
<a name="l00101"></a>00101 {
<a name="l00102"></a>00102 <a class="code" href="ckd__alloc_8h.html#a31c6b405558620ac37599737b5722fbf" title="Test and free a 1-D array.">ckd_free</a>(agc);
<a name="l00103"></a>00103 }
<a name="l00104"></a>00104
<a name="l00108"></a>00108 <span class="keywordtype">void</span>
<a name="l00109"></a><a class="code" href="agc_8h.html#a29a2a4dd80141af1c3476094c353b739">00109</a> <a class="code" href="agc_8h.html#a29a2a4dd80141af1c3476094c353b739" title="Apply AGC to the given mfc vectors (normalize all C0 mfc coefficients in the given input such that th...">agc_max</a>(<a class="code" href="structagc__s.html" title="Structure holding data for doing AGC.">agc_t</a> *agc, mfcc_t **mfc, int32 n_frame)
<a name="l00110"></a>00110 {
<a name="l00111"></a>00111 int32 i;
<a name="l00112"></a>00112
<a name="l00113"></a>00113 <span class="keywordflow">if</span> (n_frame <= 0)
<a name="l00114"></a>00114 <span class="keywordflow">return</span>;
<a name="l00115"></a>00115 agc-><a class="code" href="structagc__s.html#a20c5289a6328895101e89cc3b418a1e4" title="Observed max in current utterance.">obs_max</a> = mfc[0][0];
<a name="l00116"></a>00116 <span class="keywordflow">for</span> (i = 1; i < n_frame; i++) {
<a name="l00117"></a>00117 <span class="keywordflow">if</span> (mfc[i][0] > agc-><a class="code" href="structagc__s.html#a20c5289a6328895101e89cc3b418a1e4" title="Observed max in current utterance.">obs_max</a>) {
<a name="l00118"></a>00118 agc-><a class="code" href="structagc__s.html#a20c5289a6328895101e89cc3b418a1e4" title="Observed max in current utterance.">obs_max</a> = mfc[i][0];
<a name="l00119"></a>00119 agc-><a class="code" href="structagc__s.html#a5a6c2e967089085bd4f6020876bcb92a" title="Whether any data was observed after prev update.">obs_frame</a> = 1;
<a name="l00120"></a>00120 }
<a name="l00121"></a>00121 }
<a name="l00122"></a>00122
<a name="l00123"></a>00123 <a class="code" href="err_8h.html#ac3c705943d946708cea0a1443be1c853" title="Print logging information to standard error stream.">E_INFO</a>(<span class="stringliteral">"AGCMax: obs=max= %.2f\n"</span>, agc-><a class="code" href="structagc__s.html#a20c5289a6328895101e89cc3b418a1e4" title="Observed max in current utterance.">obs_max</a>);
<a name="l00124"></a>00124 <span class="keywordflow">for</span> (i = 0; i < n_frame; i++)
<a name="l00125"></a>00125 mfc[i][0] -= agc-><a class="code" href="structagc__s.html#a20c5289a6328895101e89cc3b418a1e4" title="Observed max in current utterance.">obs_max</a>;
<a name="l00126"></a>00126 }
<a name="l00127"></a>00127
<a name="l00128"></a>00128 <span class="keywordtype">void</span>
<a name="l00129"></a><a class="code" href="agc_8h.html#a4fd17f224b5d8f7bfcaa9389d11716eb">00129</a> <a class="code" href="agc_8h.html#a4fd17f224b5d8f7bfcaa9389d11716eb" title="Set the current AGC maximum estimate.">agc_emax_set</a>(<a class="code" href="structagc__s.html" title="Structure holding data for doing AGC.">agc_t</a> *agc, float32 m)
<a name="l00130"></a>00130 {
<a name="l00131"></a>00131 agc-><a class="code" href="structagc__s.html#a6a55c54c76a2e0373a907d186b89fa8e" title="Estimated max for current utterance (for AGC_EMAX)">max</a> = FLOAT2MFCC(m);
<a name="l00132"></a>00132 <a class="code" href="err_8h.html#ac3c705943d946708cea0a1443be1c853" title="Print logging information to standard error stream.">E_INFO</a>(<span class="stringliteral">"AGCEMax: max= %.2f\n"</span>, m);
<a name="l00133"></a>00133 }
<a name="l00134"></a>00134
<a name="l00135"></a>00135 float32
<a name="l00136"></a><a class="code" href="agc_8h.html#a7b439fb5d36250d09bb9d459c1e28ba5">00136</a> <a class="code" href="agc_8h.html#a7b439fb5d36250d09bb9d459c1e28ba5" title="Get the current AGC maximum estimate.">agc_emax_get</a>(<a class="code" href="structagc__s.html" title="Structure holding data for doing AGC.">agc_t</a> *agc)
<a name="l00137"></a>00137 {
<a name="l00138"></a>00138 <span class="keywordflow">return</span> MFCC2FLOAT(agc-><a class="code" href="structagc__s.html#a6a55c54c76a2e0373a907d186b89fa8e" title="Estimated max for current utterance (for AGC_EMAX)">max</a>);
<a name="l00139"></a>00139 }
<a name="l00140"></a>00140
<a name="l00141"></a>00141 <span class="keywordtype">void</span>
<a name="l00142"></a><a class="code" href="agc_8h.html#ac2cdd4c519b46824c5b28c5b769b5ecd">00142</a> <a class="code" href="agc_8h.html#ac2cdd4c519b46824c5b28c5b769b5ecd" title="Apply AGC to the given block of MFC vectors.">agc_emax</a>(<a class="code" href="structagc__s.html" title="Structure holding data for doing AGC.">agc_t</a> *agc, mfcc_t **mfc, int32 n_frame)
<a name="l00143"></a>00143 {
<a name="l00144"></a>00144 <span class="keywordtype">int</span> i;
<a name="l00145"></a>00145
<a name="l00146"></a>00146 <span class="keywordflow">if</span> (n_frame <= 0)
<a name="l00147"></a>00147 <span class="keywordflow">return</span>;
<a name="l00148"></a>00148 <span class="keywordflow">for</span> (i = 1; i < n_frame; ++i) {
<a name="l00149"></a>00149 <span class="keywordflow">if</span> (mfc[i][0] > agc-><a class="code" href="structagc__s.html#a20c5289a6328895101e89cc3b418a1e4" title="Observed max in current utterance.">obs_max</a>) {
<a name="l00150"></a>00150 agc-><a class="code" href="structagc__s.html#a20c5289a6328895101e89cc3b418a1e4" title="Observed max in current utterance.">obs_max</a> = mfc[i][0];
<a name="l00151"></a>00151 agc-><a class="code" href="structagc__s.html#a5a6c2e967089085bd4f6020876bcb92a" title="Whether any data was observed after prev update.">obs_frame</a> = 1;
<a name="l00152"></a>00152 }
<a name="l00153"></a>00153 mfc[i][0] -= agc-><a class="code" href="structagc__s.html#a6a55c54c76a2e0373a907d186b89fa8e" title="Estimated max for current utterance (for AGC_EMAX)">max</a>;
<a name="l00154"></a>00154 }
<a name="l00155"></a>00155 }
<a name="l00156"></a>00156
<a name="l00157"></a>00157 <span class="comment">/* Update estimated max for next utterance */</span>
<a name="l00158"></a>00158 <span class="keywordtype">void</span>
<a name="l00159"></a><a class="code" href="agc_8h.html#af47b6004f2f963ae0019a67450b892c2">00159</a> <a class="code" href="agc_8h.html#af47b6004f2f963ae0019a67450b892c2" title="Update AGC parameters for next utterance.">agc_emax_update</a>(<a class="code" href="structagc__s.html" title="Structure holding data for doing AGC.">agc_t</a> *agc)
<a name="l00160"></a>00160 {
<a name="l00161"></a>00161 <span class="keywordflow">if</span> (agc-><a class="code" href="structagc__s.html#a5a6c2e967089085bd4f6020876bcb92a" title="Whether any data was observed after prev update.">obs_frame</a>) { <span class="comment">/* Update only if some data observed */</span>
<a name="l00162"></a>00162 agc->obs_max_sum += agc-><a class="code" href="structagc__s.html#a20c5289a6328895101e89cc3b418a1e4" title="Observed max in current utterance.">obs_max</a>;
<a name="l00163"></a>00163 agc-><a class="code" href="structagc__s.html#ae4ce95dcfb26c7f14ea316ac3ab202b2" title="Whether any utterances have been observed.">obs_utt</a>++;
<a name="l00164"></a>00164
<a name="l00165"></a>00165 <span class="comment">/* Re-estimate max over past history; decay the history */</span>
<a name="l00166"></a>00166 agc-><a class="code" href="structagc__s.html#a6a55c54c76a2e0373a907d186b89fa8e" title="Estimated max for current utterance (for AGC_EMAX)">max</a> = agc->obs_max_sum / agc-><a class="code" href="structagc__s.html#ae4ce95dcfb26c7f14ea316ac3ab202b2" title="Whether any utterances have been observed.">obs_utt</a>;
<a name="l00167"></a>00167 <span class="keywordflow">if</span> (agc-><a class="code" href="structagc__s.html#ae4ce95dcfb26c7f14ea316ac3ab202b2" title="Whether any utterances have been observed.">obs_utt</a> == 8) {
<a name="l00168"></a>00168 agc->obs_max_sum /= 2;
<a name="l00169"></a>00169 agc-><a class="code" href="structagc__s.html#ae4ce95dcfb26c7f14ea316ac3ab202b2" title="Whether any utterances have been observed.">obs_utt</a> = 4;
<a name="l00170"></a>00170 }
<a name="l00171"></a>00171 }
<a name="l00172"></a>00172 <a class="code" href="err_8h.html#ac3c705943d946708cea0a1443be1c853" title="Print logging information to standard error stream.">E_INFO</a>(<span class="stringliteral">"AGCEMax: obs= %.2f, new= %.2f\n"</span>, agc-><a class="code" href="structagc__s.html#a20c5289a6328895101e89cc3b418a1e4" title="Observed max in current utterance.">obs_max</a>, agc-><a class="code" href="structagc__s.html#a6a55c54c76a2e0373a907d186b89fa8e" title="Estimated max for current utterance (for AGC_EMAX)">max</a>);
<a name="l00173"></a>00173
<a name="l00174"></a>00174 <span class="comment">/* Reset the accumulators for the next utterance. */</span>
<a name="l00175"></a>00175 agc-><a class="code" href="structagc__s.html#a5a6c2e967089085bd4f6020876bcb92a" title="Whether any data was observed after prev update.">obs_frame</a> = 0;
<a name="l00176"></a>00176 agc-><a class="code" href="structagc__s.html#a20c5289a6328895101e89cc3b418a1e4" title="Observed max in current utterance.">obs_max</a> = FLOAT2MFCC(-1000.0); <span class="comment">/* Less than any real C0 value (hopefully!!) */</span>
<a name="l00177"></a>00177 }
<a name="l00178"></a>00178
<a name="l00179"></a>00179 <span class="keywordtype">void</span>
<a name="l00180"></a><a class="code" href="agc_8h.html#ae65d4be1d74aea11b7e16e3777272d13">00180</a> <a class="code" href="agc_8h.html#ae65d4be1d74aea11b7e16e3777272d13" title="Apply AGC using noise threshold to the given block of MFC vectors.">agc_noise</a>(<a class="code" href="structagc__s.html" title="Structure holding data for doing AGC.">agc_t</a> *agc,
<a name="l00181"></a>00181 mfcc_t **cep,
<a name="l00182"></a>00182 int32 nfr)
<a name="l00183"></a>00183 {
<a name="l00184"></a>00184 mfcc_t min_energy; <span class="comment">/* Minimum log-energy */</span>
<a name="l00185"></a>00185 mfcc_t noise_level; <span class="comment">/* Average noise_level */</span>
<a name="l00186"></a>00186 int32 i; <span class="comment">/* frame index */</span>
<a name="l00187"></a>00187 int32 noise_frames; <span class="comment">/* Number of noise frames */</span>
<a name="l00188"></a>00188
<a name="l00189"></a>00189 <span class="comment">/* Determine minimum log-energy in utterance */</span>
<a name="l00190"></a>00190 min_energy = cep[0][0];
<a name="l00191"></a>00191 <span class="keywordflow">for</span> (i = 0; i < nfr; ++i) {
<a name="l00192"></a>00192 <span class="keywordflow">if</span> (cep[i][0] < min_energy)
<a name="l00193"></a>00193 min_energy = cep[i][0];
<a name="l00194"></a>00194 }
<a name="l00195"></a>00195
<a name="l00196"></a>00196 <span class="comment">/* Average all frames between min_energy and min_energy + agc->noise_thresh */</span>
<a name="l00197"></a>00197 noise_frames = 0;
<a name="l00198"></a>00198 noise_level = 0;
<a name="l00199"></a>00199 min_energy += agc-><a class="code" href="structagc__s.html#a4c896e65da00c79b77b23272474fcffc" title="Noise threshold (for AGC_NOISE only)">noise_thresh</a>;
<a name="l00200"></a>00200 <span class="keywordflow">for</span> (i = 0; i < nfr; ++i) {
<a name="l00201"></a>00201 <span class="keywordflow">if</span> (cep[i][0] < min_energy) {
<a name="l00202"></a>00202 noise_level += cep[i][0];
<a name="l00203"></a>00203 noise_frames++;
<a name="l00204"></a>00204 }
<a name="l00205"></a>00205 }
<a name="l00206"></a>00206 noise_level /= noise_frames;
<a name="l00207"></a>00207
<a name="l00208"></a>00208 <a class="code" href="err_8h.html#ac3c705943d946708cea0a1443be1c853" title="Print logging information to standard error stream.">E_INFO</a>(<span class="stringliteral">"AGC NOISE: max= %6.3f\n"</span>, MFCC2FLOAT(noise_level));
<a name="l00209"></a>00209
<a name="l00210"></a>00210 <span class="comment">/* Subtract noise_level from all log_energy values */</span>
<a name="l00211"></a>00211 <span class="keywordflow">for</span> (i = 0; i < nfr; ++i)
<a name="l00212"></a>00212 cep[i][0] -= noise_level;
<a name="l00213"></a>00213 }
<a name="l00214"></a>00214
<a name="l00215"></a>00215 <span class="keywordtype">void</span>
<a name="l00216"></a><a class="code" href="agc_8h.html#aaaa9e15f192c91ad64c343b7c6db6714">00216</a> <a class="code" href="agc_8h.html#aaaa9e15f192c91ad64c343b7c6db6714" title="Set the current AGC noise threshold.">agc_set_threshold</a>(<a class="code" href="structagc__s.html" title="Structure holding data for doing AGC.">agc_t</a> *agc, float32 threshold)
<a name="l00217"></a>00217 {
<a name="l00218"></a>00218 agc-><a class="code" href="structagc__s.html#a4c896e65da00c79b77b23272474fcffc" title="Noise threshold (for AGC_NOISE only)">noise_thresh</a> = FLOAT2MFCC(threshold);
<a name="l00219"></a>00219 }
<a name="l00220"></a>00220
<a name="l00221"></a>00221 float32
<a name="l00222"></a><a class="code" href="agc_8h.html#a77d0987174a1b3c6e8fcd63fe82f33ce">00222</a> <a class="code" href="agc_8h.html#a77d0987174a1b3c6e8fcd63fe82f33ce" title="Get the current AGC noise threshold.">agc_get_threshold</a>(<a class="code" href="structagc__s.html" title="Structure holding data for doing AGC.">agc_t</a> *agc)
<a name="l00223"></a>00223 {
<a name="l00224"></a>00224 <span class="keywordflow">return</span> FLOAT2MFCC(agc-><a class="code" href="structagc__s.html#a4c896e65da00c79b77b23272474fcffc" title="Noise threshold (for AGC_NOISE only)">noise_thresh</a>);
<a name="l00225"></a>00225 }
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