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<h1>src/libsphinxbase/fe/fe_sigproc.c</h1> </div>
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<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) 1996-2004 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
<a name="l00038"></a>00038 <span class="preprocessor">#include <stdio.h></span>
<a name="l00039"></a>00039 <span class="preprocessor">#include <math.h></span>
<a name="l00040"></a>00040 <span class="preprocessor">#include <string.h></span>
<a name="l00041"></a>00041 <span class="preprocessor">#include <stdlib.h></span>
<a name="l00042"></a>00042 <span class="preprocessor">#include <assert.h></span>
<a name="l00043"></a>00043
<a name="l00044"></a>00044 <span class="preprocessor">#ifdef HAVE_CONFIG_H</span>
<a name="l00045"></a>00045 <span class="preprocessor"></span><span class="preprocessor">#include <config.h></span>
<a name="l00046"></a>00046 <span class="preprocessor">#endif</span>
<a name="l00047"></a>00047 <span class="preprocessor"></span>
<a name="l00048"></a>00048 <span class="preprocessor">#ifdef _MSC_VER</span>
<a name="l00049"></a>00049 <span class="preprocessor"></span><span class="preprocessor">#pragma warning (disable: 4244)</span>
<a name="l00050"></a>00050 <span class="preprocessor"></span><span class="preprocessor">#endif</span>
<a name="l00051"></a>00051 <span class="preprocessor"></span>
<a name="l00052"></a>00052 <span class="preprocessor">#include "sphinxbase/prim_type.h"</span>
<a name="l00053"></a>00053 <span class="preprocessor">#include "sphinxbase/ckd_alloc.h"</span>
<a name="l00054"></a>00054 <span class="preprocessor">#include "sphinxbase/byteorder.h"</span>
<a name="l00055"></a>00055 <span class="preprocessor">#include "sphinxbase/fixpoint.h"</span>
<a name="l00056"></a>00056 <span class="preprocessor">#include "sphinxbase/fe.h"</span>
<a name="l00057"></a>00057 <span class="preprocessor">#include "sphinxbase/genrand.h"</span>
<a name="l00058"></a>00058 <span class="preprocessor">#include "sphinxbase/libutil.h"</span>
<a name="l00059"></a>00059 <span class="preprocessor">#include "sphinxbase/err.h"</span>
<a name="l00060"></a>00060
<a name="l00061"></a>00061 <span class="preprocessor">#include "fe_internal.h"</span>
<a name="l00062"></a>00062 <span class="preprocessor">#include "fe_warp.h"</span>
<a name="l00063"></a>00063
<a name="l00064"></a>00064 <span class="comment">/* Use extra precision for cosines, Hamming window, pre-emphasis</span>
<a name="l00065"></a>00065 <span class="comment"> * coefficient, twiddle factors. */</span>
<a name="l00066"></a>00066 <span class="preprocessor">#ifdef FIXED_POINT</span>
<a name="l00067"></a>00067 <span class="preprocessor"></span><span class="preprocessor">#define FLOAT2COS(x) FLOAT2FIX_ANY(x,30)</span>
<a name="l00068"></a>00068 <span class="preprocessor"></span><span class="preprocessor">#define COSMUL(x,y) FIXMUL_ANY(x,y,30)</span>
<a name="l00069"></a>00069 <span class="preprocessor"></span><span class="preprocessor">#else</span>
<a name="l00070"></a>00070 <span class="preprocessor"></span><span class="preprocessor">#define FLOAT2COS(x) (x)</span>
<a name="l00071"></a>00071 <span class="preprocessor"></span><span class="preprocessor">#define COSMUL(x,y) ((x)*(y))</span>
<a name="l00072"></a>00072 <span class="preprocessor"></span><span class="preprocessor">#endif</span>
<a name="l00073"></a>00073 <span class="preprocessor"></span>
<a name="l00074"></a>00074 <span class="preprocessor">#ifdef FIXED_POINT</span>
<a name="l00075"></a>00075 <span class="preprocessor"></span><span class="comment">/* Internal log-addition table for natural log with radix point at 8</span>
<a name="l00076"></a>00076 <span class="comment"> * bits. Each entry is 256 * log(1 + e^{-n/256}). This is used in the</span>
<a name="l00077"></a>00077 <span class="comment"> * log-add computation:</span>
<a name="l00078"></a>00078 <span class="comment"> *</span>
<a name="l00079"></a>00079 <span class="comment"> * e^z = e^x + e^y</span>
<a name="l00080"></a>00080 <span class="comment"> * e^z = e^x(1 + e^{y-x}) = e^y(1 + e^{x-y})</span>
<a name="l00081"></a>00081 <span class="comment"> * z = x + log(1 + e^{y-x}) = y + log(1 + e^{x-y})</span>
<a name="l00082"></a>00082 <span class="comment"> *</span>
<a name="l00083"></a>00083 <span class="comment"> * So when y > x, z = y + logadd_table[-(x-y)]</span>
<a name="l00084"></a>00084 <span class="comment"> * when x > y, z = x + logadd_table[-(y-x)]</span>
<a name="l00085"></a>00085 <span class="comment"> */</span>
<a name="l00086"></a>00086 <span class="keyword">static</span> <span class="keyword">const</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> fe_logadd_table[] = {
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<a name="l00098"></a>00098 128, 128, 128, 127, 127, 126, 126, 126, 125, 125,
<a name="l00099"></a>00099 124, 124, 124, 123, 123, 123, 122, 122, 121, 121,
<a name="l00100"></a>00100 121, 120, 120, 119, 119, 119, 118, 118, 118, 117,
<a name="l00101"></a>00101 117, 117, 116, 116, 115, 115, 115, 114, 114, 114,
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<a name="l00103"></a>00103 110, 109, 109, 109, 108, 108, 108, 107, 107, 107,
<a name="l00104"></a>00104 106, 106, 106, 105, 105, 105, 104, 104, 104, 103,
<a name="l00105"></a>00105 103, 103, 102, 102, 102, 101, 101, 101, 100, 100,
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<a name="l00216"></a>00216 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
<a name="l00217"></a>00217 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
<a name="l00218"></a>00218 2, 2, 2, 2, 2, 2, 1, 1, 1, 1,
<a name="l00219"></a>00219 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00220"></a>00220 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00221"></a>00221 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00222"></a>00222 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00223"></a>00223 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00224"></a>00224 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00225"></a>00225 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00226"></a>00226 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00227"></a>00227 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00228"></a>00228 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00229"></a>00229 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00230"></a>00230 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00231"></a>00231 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00232"></a>00232 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00233"></a>00233 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00234"></a>00234 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00235"></a>00235 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00236"></a>00236 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00237"></a>00237 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00238"></a>00238 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00239"></a>00239 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00240"></a>00240 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00241"></a>00241 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00242"></a>00242 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00243"></a>00243 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00244"></a>00244 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00245"></a>00245 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
<a name="l00246"></a>00246 1, 1, 1, 1, 1, 1, 1, 0
<a name="l00247"></a>00247 };
<a name="l00248"></a>00248 <span class="keyword">static</span> <span class="keyword">const</span> <span class="keywordtype">int</span> fe_logadd_table_size = <span class="keyword">sizeof</span>(fe_logadd_table) / <span class="keyword">sizeof</span>(fe_logadd_table[0]);
<a name="l00249"></a>00249
<a name="l00250"></a>00250 <span class="keyword">static</span> fixed32
<a name="l00251"></a>00251 fe_log_add(fixed32 x, fixed32 y)
<a name="l00252"></a>00252 {
<a name="l00253"></a>00253 fixed32 d, r;
<a name="l00254"></a>00254
<a name="l00255"></a>00255 <span class="keywordflow">if</span> (x > y) {
<a name="l00256"></a>00256 d = (x - y) >> (DEFAULT_RADIX - 8);
<a name="l00257"></a>00257 r = x;
<a name="l00258"></a>00258 }
<a name="l00259"></a>00259 <span class="keywordflow">else</span> {
<a name="l00260"></a>00260 d = (y - x) >> (DEFAULT_RADIX - 8);
<a name="l00261"></a>00261 r = y;
<a name="l00262"></a>00262 }
<a name="l00263"></a>00263 <span class="keywordflow">if</span> (d > fe_logadd_table_size)
<a name="l00264"></a>00264 <span class="keywordflow">return</span> r;
<a name="l00265"></a>00265 <span class="keywordflow">else</span> {
<a name="l00266"></a>00266 r += ((fixed32)fe_logadd_table[d] << (DEFAULT_RADIX - 8));
<a name="l00267"></a>00267 <span class="comment">/*</span>
<a name="l00268"></a>00268 <span class="comment"> printf("%d + %d = %d | %f + %f = %f | %f + %f = %f\n",</span>
<a name="l00269"></a>00269 <span class="comment"> x, y, r, FIX2FLOAT(x), FIX2FLOAT(y), FIX2FLOAT(r),</span>
<a name="l00270"></a>00270 <span class="comment"> exp(FIX2FLOAT(x)), exp(FIX2FLOAT(y)), exp(FIX2FLOAT(r)));</span>
<a name="l00271"></a>00271 <span class="comment">*/</span>
<a name="l00272"></a>00272 <span class="keywordflow">return</span> r;
<a name="l00273"></a>00273 }
<a name="l00274"></a>00274 }
<a name="l00275"></a>00275
<a name="l00276"></a>00276 <span class="keyword">static</span> fixed32
<a name="l00277"></a>00277 fe_log(float32 x)
<a name="l00278"></a>00278 {
<a name="l00279"></a>00279 <span class="keywordflow">if</span> (x <= 0) {
<a name="l00280"></a>00280 <span class="keywordflow">return</span> MIN_FIXLOG;
<a name="l00281"></a>00281 }
<a name="l00282"></a>00282 <span class="keywordflow">else</span> {
<a name="l00283"></a>00283 <span class="keywordflow">return</span> FLOAT2FIX(log(x));
<a name="l00284"></a>00284 }
<a name="l00285"></a>00285 }
<a name="l00286"></a>00286 <span class="preprocessor">#endif</span>
<a name="l00287"></a>00287 <span class="preprocessor"></span>
<a name="l00288"></a>00288 <span class="keyword">static</span> float32
<a name="l00289"></a>00289 fe_mel(<a class="code" href="structmelfb__s.html" title="Base Struct to hold all structure for MFCC computation.">melfb_t</a> *mel, float32 x)
<a name="l00290"></a>00290 {
<a name="l00291"></a>00291 float32 warped = fe_warp_unwarped_to_warped(mel, x);
<a name="l00292"></a>00292
<a name="l00293"></a>00293 <span class="keywordflow">return</span> (float32) (2595.0 * log10(1.0 + warped / 700.0));
<a name="l00294"></a>00294 }
<a name="l00295"></a>00295
<a name="l00296"></a>00296 <span class="keyword">static</span> float32
<a name="l00297"></a>00297 fe_melinv(<a class="code" href="structmelfb__s.html" title="Base Struct to hold all structure for MFCC computation.">melfb_t</a> *mel, float32 x)
<a name="l00298"></a>00298 {
<a name="l00299"></a>00299 float32 warped = (float32) (700.0 * (pow(10.0, x / 2595.0) - 1.0));
<a name="l00300"></a>00300 <span class="keywordflow">return</span> fe_warp_warped_to_unwarped(mel, warped);
<a name="l00301"></a>00301 }
<a name="l00302"></a>00302
<a name="l00303"></a>00303 int32
<a name="l00304"></a>00304 fe_build_melfilters(<a class="code" href="structmelfb__s.html" title="Base Struct to hold all structure for MFCC computation.">melfb_t</a> *mel_fb)
<a name="l00305"></a>00305 {
<a name="l00306"></a>00306 float32 melmin, melmax, melbw, fftfreq;
<a name="l00307"></a>00307 <span class="keywordtype">int</span> n_coeffs, i, j;
<a name="l00308"></a>00308
<a name="l00309"></a>00309 <span class="comment">/* Filter coefficient matrix, in flattened form. */</span>
<a name="l00310"></a>00310 mel_fb->spec_start = <a class="code" href="ckd__alloc_8h.html#a8e89a31c3c70710a8e023a177084bff2" title="Macro for __ckd_malloc__.">ckd_malloc</a>(mel_fb->num_filters * <span class="keyword">sizeof</span>(*mel_fb->spec_start));
<a name="l00311"></a>00311 mel_fb->filt_start = <a class="code" href="ckd__alloc_8h.html#a8e89a31c3c70710a8e023a177084bff2" title="Macro for __ckd_malloc__.">ckd_malloc</a>(mel_fb->num_filters * <span class="keyword">sizeof</span>(*mel_fb->filt_start));
<a name="l00312"></a>00312 mel_fb->filt_width = <a class="code" href="ckd__alloc_8h.html#a8e89a31c3c70710a8e023a177084bff2" title="Macro for __ckd_malloc__.">ckd_malloc</a>(mel_fb->num_filters * <span class="keyword">sizeof</span>(*mel_fb->filt_width));
<a name="l00313"></a>00313
<a name="l00314"></a>00314 <span class="comment">/* First calculate the widths of each filter. */</span>
<a name="l00315"></a>00315 <span class="comment">/* Minimum and maximum frequencies in mel scale. */</span>
<a name="l00316"></a>00316 melmin = fe_mel(mel_fb, mel_fb->lower_filt_freq);
<a name="l00317"></a>00317 melmax = fe_mel(mel_fb, mel_fb->upper_filt_freq);
<a name="l00318"></a>00318
<a name="l00319"></a>00319 <span class="comment">/* Width of filters in mel scale */</span>
<a name="l00320"></a>00320 melbw = (melmax - melmin) / (mel_fb->num_filters + 1);
<a name="l00321"></a>00321 <span class="keywordflow">if</span> (mel_fb->doublewide) {
<a name="l00322"></a>00322 melmin -= melbw;
<a name="l00323"></a>00323 melmax += melbw;
<a name="l00324"></a>00324 <span class="keywordflow">if</span> ((fe_melinv(mel_fb, melmin) < 0) ||
<a name="l00325"></a>00325 (fe_melinv(mel_fb, melmax) > mel_fb->sampling_rate / 2)) {
<a name="l00326"></a>00326 <a class="code" href="err_8h.html#a6a794bec721b555ac1f2167f9e12f662" title="Print warning information to standard error stream.">E_WARN</a>
<a name="l00327"></a>00327 (<span class="stringliteral">"Out of Range: low filter edge = %f (%f)\n"</span>,
<a name="l00328"></a>00328 fe_melinv(mel_fb, melmin), 0.0);
<a name="l00329"></a>00329 <a class="code" href="err_8h.html#a6a794bec721b555ac1f2167f9e12f662" title="Print warning information to standard error stream.">E_WARN</a>
<a name="l00330"></a>00330 (<span class="stringliteral">" high filter edge = %f (%f)\n"</span>,
<a name="l00331"></a>00331 fe_melinv(mel_fb, melmax), mel_fb->sampling_rate / 2);
<a name="l00332"></a>00332 <span class="keywordflow">return</span> FE_INVALID_PARAM_ERROR;
<a name="l00333"></a>00333 }
<a name="l00334"></a>00334 }
<a name="l00335"></a>00335
<a name="l00336"></a>00336 <span class="comment">/* DFT point spacing */</span>
<a name="l00337"></a>00337 fftfreq = mel_fb->sampling_rate / (float32) mel_fb->fft_size;
<a name="l00338"></a>00338
<a name="l00339"></a>00339 <span class="comment">/* Count and place filter coefficients. */</span>
<a name="l00340"></a>00340 n_coeffs = 0;
<a name="l00341"></a>00341 for (i = 0; i < mel_fb->num_filters; ++i) {
<a name="l00342"></a>00342 float32 freqs[3];
<a name="l00343"></a>00343
<a name="l00344"></a>00344 <span class="comment">/* Left, center, right frequencies in Hertz */</span>
<a name="l00345"></a>00345 <span class="keywordflow">for</span> (j = 0; j < 3; ++j) {
<a name="l00346"></a>00346 <span class="keywordflow">if</span> (mel_fb->doublewide)
<a name="l00347"></a>00347 freqs[j] = fe_melinv(mel_fb, (i + j * 2) * melbw + melmin);
<a name="l00348"></a>00348 <span class="keywordflow">else</span>
<a name="l00349"></a>00349 freqs[j] = fe_melinv(mel_fb, (i + j) * melbw + melmin);
<a name="l00350"></a>00350 <span class="comment">/* Round them to DFT points if requested */</span>
<a name="l00351"></a>00351 <span class="keywordflow">if</span> (mel_fb->round_filters)
<a name="l00352"></a>00352 freqs[j] = ((int)(freqs[j] / fftfreq + 0.5)) * fftfreq;
<a name="l00353"></a>00353 }
<a name="l00354"></a>00354
<a name="l00355"></a>00355 <span class="comment">/* spec_start is the start of this filter in the power spectrum. */</span>
<a name="l00356"></a>00356 mel_fb->spec_start[i] = -1;
<a name="l00357"></a>00357 <span class="comment">/* There must be a better way... */</span>
<a name="l00358"></a>00358 <span class="keywordflow">for</span> (j = 0; j < mel_fb->fft_size/2+1; ++j) {
<a name="l00359"></a>00359 float32 hz = j * fftfreq;
<a name="l00360"></a>00360 <span class="keywordflow">if</span> (hz < freqs[0])
<a name="l00361"></a>00361 <span class="keywordflow">continue</span>;
<a name="l00362"></a>00362 <span class="keywordflow">else</span> <span class="keywordflow">if</span> (hz > freqs[2] || j == mel_fb->fft_size/2) {
<a name="l00363"></a>00363 <span class="comment">/* filt_width is the width in DFT points of this filter. */</span>
<a name="l00364"></a>00364 mel_fb->filt_width[i] = j - mel_fb->spec_start[i];
<a name="l00365"></a>00365 <span class="comment">/* filt_start is the start of this filter in the filt_coeffs array. */</span>
<a name="l00366"></a>00366 mel_fb->filt_start[i] = n_coeffs;
<a name="l00367"></a>00367 n_coeffs += mel_fb->filt_width[i];
<a name="l00368"></a>00368 <span class="keywordflow">break</span>;
<a name="l00369"></a>00369 }
<a name="l00370"></a>00370 <span class="keywordflow">if</span> (mel_fb->spec_start[i] == -1)
<a name="l00371"></a>00371 mel_fb->spec_start[i] = j;
<a name="l00372"></a>00372 }
<a name="l00373"></a>00373 }
<a name="l00374"></a>00374
<a name="l00375"></a>00375 <span class="comment">/* Now go back and allocate the coefficient array. */</span>
<a name="l00376"></a>00376 mel_fb->filt_coeffs = <a class="code" href="ckd__alloc_8h.html#a8e89a31c3c70710a8e023a177084bff2" title="Macro for __ckd_malloc__.">ckd_malloc</a>(n_coeffs * <span class="keyword">sizeof</span>(*mel_fb->filt_coeffs));
<a name="l00377"></a>00377
<a name="l00378"></a>00378 <span class="comment">/* And now generate the coefficients. */</span>
<a name="l00379"></a>00379 n_coeffs = 0;
<a name="l00380"></a>00380 <span class="keywordflow">for</span> (i = 0; i < mel_fb->num_filters; ++i) {
<a name="l00381"></a>00381 float32 freqs[3];
<a name="l00382"></a>00382
<a name="l00383"></a>00383 <span class="comment">/* Left, center, right frequencies in Hertz */</span>
<a name="l00384"></a>00384 <span class="keywordflow">for</span> (j = 0; j < 3; ++j) {
<a name="l00385"></a>00385 <span class="keywordflow">if</span> (mel_fb->doublewide)
<a name="l00386"></a>00386 freqs[j] = fe_melinv(mel_fb, (i + j * 2) * melbw + melmin);
<a name="l00387"></a>00387 <span class="keywordflow">else</span>
<a name="l00388"></a>00388 freqs[j] = fe_melinv(mel_fb, (i + j) * melbw + melmin);
<a name="l00389"></a>00389 <span class="comment">/* Round them to DFT points if requested */</span>
<a name="l00390"></a>00390 <span class="keywordflow">if</span> (mel_fb->round_filters)
<a name="l00391"></a>00391 freqs[j] = ((int)(freqs[j] / fftfreq + 0.5)) * fftfreq;
<a name="l00392"></a>00392 }
<a name="l00393"></a>00393
<a name="l00394"></a>00394 <span class="keywordflow">for</span> (j = 0; j < mel_fb->filt_width[i]; ++j) {
<a name="l00395"></a>00395 float32 hz, loslope, hislope;
<a name="l00396"></a>00396
<a name="l00397"></a>00397 hz = (mel_fb->spec_start[i] + j) * fftfreq;
<a name="l00398"></a>00398 <span class="keywordflow">if</span> (hz < freqs[0] || hz > freqs[2]) {
<a name="l00399"></a>00399 <a class="code" href="err_8h.html#a1a4495946ab2449d61108fe829a94613" title="Exit with non-zero status after error message.">E_FATAL</a>(<span class="stringliteral">"WTF, %f < %f > %f\n"</span>, freqs[0], hz, freqs[2]);
<a name="l00400"></a>00400 }
<a name="l00401"></a>00401 loslope = (hz - freqs[0]) / (freqs[1] - freqs[0]);
<a name="l00402"></a>00402 hislope = (freqs[2] - hz) / (freqs[2] - freqs[1]);
<a name="l00403"></a>00403 <span class="keywordflow">if</span> (mel_fb->unit_area) {
<a name="l00404"></a>00404 loslope *= 2 / (freqs[2] - freqs[0]);
<a name="l00405"></a>00405 hislope *= 2 / (freqs[2] - freqs[0]);
<a name="l00406"></a>00406 }
<a name="l00407"></a>00407 <span class="keywordflow">if</span> (loslope < hislope) {
<a name="l00408"></a>00408 <span class="preprocessor">#ifdef FIXED_POINT</span>
<a name="l00409"></a>00409 <span class="preprocessor"></span> mel_fb->filt_coeffs[n_coeffs] = fe_log(loslope);
<a name="l00410"></a>00410 <span class="preprocessor">#else</span>
<a name="l00411"></a>00411 <span class="preprocessor"></span> mel_fb->filt_coeffs[n_coeffs] = loslope;
<a name="l00412"></a>00412 <span class="preprocessor">#endif</span>
<a name="l00413"></a>00413 <span class="preprocessor"></span> }
<a name="l00414"></a>00414 <span class="keywordflow">else</span> {
<a name="l00415"></a>00415 <span class="preprocessor">#ifdef FIXED_POINT</span>
<a name="l00416"></a>00416 <span class="preprocessor"></span> mel_fb->filt_coeffs[n_coeffs] = fe_log(hislope);
<a name="l00417"></a>00417 <span class="preprocessor">#else</span>
<a name="l00418"></a>00418 <span class="preprocessor"></span> mel_fb->filt_coeffs[n_coeffs] = hislope;
<a name="l00419"></a>00419 <span class="preprocessor">#endif</span>
<a name="l00420"></a>00420 <span class="preprocessor"></span> }
<a name="l00421"></a>00421 ++n_coeffs;
<a name="l00422"></a>00422 }
<a name="l00423"></a>00423 }
<a name="l00424"></a>00424
<a name="l00425"></a>00425
<a name="l00426"></a>00426 <span class="keywordflow">return</span> FE_SUCCESS;
<a name="l00427"></a>00427 }
<a name="l00428"></a>00428
<a name="l00429"></a>00429 int32
<a name="l00430"></a>00430 fe_compute_melcosine(<a class="code" href="structmelfb__s.html" title="Base Struct to hold all structure for MFCC computation.">melfb_t</a> * mel_fb)
<a name="l00431"></a>00431 {
<a name="l00432"></a>00432
<a name="l00433"></a>00433 float64 freqstep;
<a name="l00434"></a>00434 int32 i, j;
<a name="l00435"></a>00435
<a name="l00436"></a>00436 mel_fb->mel_cosine =
<a name="l00437"></a>00437 (mfcc_t **) <a class="code" href="ckd__alloc_8h.html#a949e7b50fcd9697b1563fa57f50e9c4f" title="Macro for __ckd_calloc_2d__.">ckd_calloc_2d</a>(mel_fb->num_cepstra,
<a name="l00438"></a>00438 mel_fb->num_filters,
<a name="l00439"></a>00439 <span class="keyword">sizeof</span>(mfcc_t));
<a name="l00440"></a>00440
<a name="l00441"></a>00441 freqstep = M_PI / mel_fb->num_filters;
<a name="l00442"></a>00442 <span class="comment">/* NOTE: The first row vector is actually unnecessary but we leave</span>
<a name="l00443"></a>00443 <span class="comment"> * it in to avoid confusion. */</span>
<a name="l00444"></a>00444 <span class="keywordflow">for</span> (i = 0; i < mel_fb->num_cepstra; i++) {
<a name="l00445"></a>00445 <span class="keywordflow">for</span> (j = 0; j < mel_fb->num_filters; j++) {
<a name="l00446"></a>00446 float64 cosine;
<a name="l00447"></a>00447
<a name="l00448"></a>00448 cosine = cos(freqstep * i * (j + 0.5));
<a name="l00449"></a>00449 mel_fb->mel_cosine[i][j] = FLOAT2COS(cosine);
<a name="l00450"></a>00450 }
<a name="l00451"></a>00451 }
<a name="l00452"></a>00452
<a name="l00453"></a>00453 <span class="comment">/* Also precompute normalization constants for unitary DCT. */</span>
<a name="l00454"></a>00454 mel_fb->sqrt_inv_n = FLOAT2COS(sqrt(1.0 / mel_fb->num_filters));
<a name="l00455"></a>00455 mel_fb->sqrt_inv_2n = FLOAT2COS(sqrt(2.0 / mel_fb->num_filters));
<a name="l00456"></a>00456
<a name="l00457"></a>00457 <span class="comment">/* And liftering weights */</span>
<a name="l00458"></a>00458 <span class="keywordflow">if</span> (mel_fb->lifter_val) {
<a name="l00459"></a>00459 mel_fb->lifter = calloc(mel_fb->num_cepstra, <span class="keyword">sizeof</span>(*mel_fb->lifter));
<a name="l00460"></a>00460 <span class="keywordflow">for</span> (i = 0; i < mel_fb->num_cepstra; ++i) {
<a name="l00461"></a>00461 mel_fb->lifter[i] = FLOAT2MFCC(1 + mel_fb->lifter_val / 2
<a name="l00462"></a>00462 * sin(i * M_PI / mel_fb->lifter_val));
<a name="l00463"></a>00463 }
<a name="l00464"></a>00464 }
<a name="l00465"></a>00465
<a name="l00466"></a>00466 <span class="keywordflow">return</span> (0);
<a name="l00467"></a>00467 }
<a name="l00468"></a>00468
<a name="l00469"></a>00469 <span class="keyword">static</span> <span class="keywordtype">void</span>
<a name="l00470"></a>00470 fe_pre_emphasis(int16 <span class="keyword">const</span> *in, frame_t * out, int32 len,
<a name="l00471"></a>00471 float32 factor, int16 prior)
<a name="l00472"></a>00472 {
<a name="l00473"></a>00473 <span class="keywordtype">int</span> i;
<a name="l00474"></a>00474
<a name="l00475"></a>00475 <span class="preprocessor">#if defined(FIXED16)</span>
<a name="l00476"></a>00476 <span class="preprocessor"></span> int16 fxd_alpha = (int16)(factor * 0x8000);
<a name="l00477"></a>00477 int32 tmp1, tmp2;
<a name="l00478"></a>00478
<a name="l00479"></a>00479 tmp1 = (int32)in[0] << 15;
<a name="l00480"></a>00480 tmp2 = (int32)prior * fxd_alpha;
<a name="l00481"></a>00481 out[0] = (int16)((tmp1 - tmp2) >> 15);
<a name="l00482"></a>00482 <span class="keywordflow">for</span> (i = 1; i < len; ++i) {
<a name="l00483"></a>00483 tmp1 = (int32)in[i] << 15;
<a name="l00484"></a>00484 tmp2 = (int32)in[i-1] * fxd_alpha;
<a name="l00485"></a>00485 out[i] = (int16)((tmp1 - tmp2) >> 15);
<a name="l00486"></a>00486 }
<a name="l00487"></a>00487 <span class="preprocessor">#elif defined(FIXED_POINT)</span>
<a name="l00488"></a>00488 <span class="preprocessor"></span> fixed32 fxd_alpha = FLOAT2FIX(factor);
<a name="l00489"></a>00489 out[0] = ((fixed32)in[0] << DEFAULT_RADIX) - (prior * fxd_alpha);
<a name="l00490"></a>00490 <span class="keywordflow">for</span> (i = 1; i < len; ++i)
<a name="l00491"></a>00491 out[i] = ((fixed32)in[i] << DEFAULT_RADIX)
<a name="l00492"></a>00492 - (fixed32)in[i-1] * fxd_alpha;
<a name="l00493"></a>00493 <span class="preprocessor">#else</span>
<a name="l00494"></a>00494 <span class="preprocessor"></span> out[0] = (frame_t) in[0] - (frame_t) prior * factor;
<a name="l00495"></a>00495 <span class="keywordflow">for</span> (i = 1; i < len; i++)
<a name="l00496"></a>00496 out[i] = (frame_t) in[i] - (frame_t) in[i-1] * factor;
<a name="l00497"></a>00497 <span class="preprocessor">#endif</span>
<a name="l00498"></a>00498 <span class="preprocessor"></span>}
<a name="l00499"></a>00499
<a name="l00500"></a>00500 <span class="keyword">static</span> <span class="keywordtype">void</span>
<a name="l00501"></a>00501 fe_short_to_frame(int16 <span class="keyword">const</span> *in, frame_t * out, int32 len)
<a name="l00502"></a>00502 {
<a name="l00503"></a>00503 <span class="keywordtype">int</span> i;
<a name="l00504"></a>00504
<a name="l00505"></a>00505 <span class="preprocessor">#if defined(FIXED16)</span>
<a name="l00506"></a>00506 <span class="preprocessor"></span> memcpy(out, in, len * <span class="keyword">sizeof</span>(*out));
<a name="l00507"></a>00507 <span class="preprocessor">#elif defined(FIXED_POINT)</span>
<a name="l00508"></a>00508 <span class="preprocessor"></span> <span class="keywordflow">for</span> (i = 0; i < len; i++)
<a name="l00509"></a>00509 out[i] = (int32) in[i] << DEFAULT_RADIX;
<a name="l00510"></a>00510 <span class="preprocessor">#else </span><span class="comment">/* FIXED_POINT */</span>
<a name="l00511"></a>00511 <span class="keywordflow">for</span> (i = 0; i < len; i++)
<a name="l00512"></a>00512 out[i] = (frame_t) in[i];
<a name="l00513"></a>00513 <span class="preprocessor">#endif </span><span class="comment">/* FIXED_POINT */</span>
<a name="l00514"></a>00514 }
<a name="l00515"></a>00515
<a name="l00516"></a>00516 <span class="keywordtype">void</span>
<a name="l00517"></a>00517 fe_create_hamming(window_t * in, int32 in_len)
<a name="l00518"></a>00518 {
<a name="l00519"></a>00519 <span class="keywordtype">int</span> i;
<a name="l00520"></a>00520
<a name="l00521"></a>00521 <span class="comment">/* Symmetric, so we only create the first half of it. */</span>
<a name="l00522"></a>00522 <span class="keywordflow">for</span> (i = 0; i < in_len / 2; i++) {
<a name="l00523"></a>00523 float64 hamm;
<a name="l00524"></a>00524 hamm = (0.54 - 0.46 * cos(2 * M_PI * i /
<a name="l00525"></a>00525 ((float64) in_len - 1.0)));
<a name="l00526"></a>00526 <span class="preprocessor">#ifdef FIXED16</span>
<a name="l00527"></a>00527 <span class="preprocessor"></span> in[i] = (int16)(hamm * 0x8000);
<a name="l00528"></a>00528 <span class="preprocessor">#else</span>
<a name="l00529"></a>00529 <span class="preprocessor"></span> in[i] = FLOAT2COS(hamm);
<a name="l00530"></a>00530 <span class="preprocessor">#endif</span>
<a name="l00531"></a>00531 <span class="preprocessor"></span> }
<a name="l00532"></a>00532 }
<a name="l00533"></a>00533
<a name="l00534"></a>00534 <span class="keyword">static</span> <span class="keywordtype">void</span>
<a name="l00535"></a>00535 fe_hamming_window(frame_t * in, window_t * window, int32 in_len, int32 remove_dc)
<a name="l00536"></a>00536 {
<a name="l00537"></a>00537 <span class="keywordtype">int</span> i;
<a name="l00538"></a>00538
<a name="l00539"></a>00539 <span class="keywordflow">if</span> (remove_dc) {
<a name="l00540"></a>00540 <span class="preprocessor">#ifdef FIXED16</span>
<a name="l00541"></a>00541 <span class="preprocessor"></span> int32 mean = 0; <span class="comment">/* Use int32 to avoid possibility of overflow */</span>
<a name="l00542"></a>00542 <span class="preprocessor">#else</span>
<a name="l00543"></a>00543 <span class="preprocessor"></span> frame_t mean = 0;
<a name="l00544"></a>00544 <span class="preprocessor">#endif</span>
<a name="l00545"></a>00545 <span class="preprocessor"></span>
<a name="l00546"></a>00546 <span class="keywordflow">for</span> (i = 0; i < in_len; i++)
<a name="l00547"></a>00547 mean += in[i];
<a name="l00548"></a>00548 mean /= in_len;
<a name="l00549"></a>00549 <span class="keywordflow">for</span> (i = 0; i < in_len; i++)
<a name="l00550"></a>00550 in[i] -= (frame_t)mean;
<a name="l00551"></a>00551 }
<a name="l00552"></a>00552
<a name="l00553"></a>00553 <span class="preprocessor">#ifdef FIXED16</span>
<a name="l00554"></a>00554 <span class="preprocessor"></span> <span class="keywordflow">for</span> (i = 0; i < in_len/2; i++) {
<a name="l00555"></a>00555 int32 tmp1, tmp2;
<a name="l00556"></a>00556
<a name="l00557"></a>00557 tmp1 = (int32)in[i] * window[i];
<a name="l00558"></a>00558 tmp2 = (int32)in[in_len-1-i] * window[i];
<a name="l00559"></a>00559 in[i] = (int16)(tmp1 >> 15);
<a name="l00560"></a>00560 in[in_len-1-i] = (int16)(tmp2 >> 15);
<a name="l00561"></a>00561 }
<a name="l00562"></a>00562 <span class="preprocessor">#else</span>
<a name="l00563"></a>00563 <span class="preprocessor"></span> <span class="keywordflow">for</span> (i = 0; i < in_len/2; i++) {
<a name="l00564"></a>00564 in[i] = COSMUL(in[i], window[i]);
<a name="l00565"></a>00565 in[in_len-1-i] = COSMUL(in[in_len-1-i], window[i]);
<a name="l00566"></a>00566 }
<a name="l00567"></a>00567 <span class="preprocessor">#endif</span>
<a name="l00568"></a>00568 <span class="preprocessor"></span>}
<a name="l00569"></a>00569
<a name="l00570"></a>00570 <span class="keyword">static</span> <span class="keywordtype">int</span>
<a name="l00571"></a>00571 fe_spch_to_frame(<a class="code" href="structfe__s.html" title="Structure for the front-end computation.">fe_t</a> *fe, <span class="keywordtype">int</span> len)
<a name="l00572"></a>00572 {
<a name="l00573"></a>00573 <span class="comment">/* Copy to the frame buffer. */</span>
<a name="l00574"></a>00574 <span class="keywordflow">if</span> (fe->pre_emphasis_alpha != 0.0) {
<a name="l00575"></a>00575 fe_pre_emphasis(fe->spch, fe->frame, len,
<a name="l00576"></a>00576 fe->pre_emphasis_alpha, fe->prior);
<a name="l00577"></a>00577 <span class="keywordflow">if</span> (len >= fe->frame_shift)
<a name="l00578"></a>00578 fe->prior = fe->spch[fe->frame_shift - 1];
<a name="l00579"></a>00579 <span class="keywordflow">else</span>
<a name="l00580"></a>00580 fe->prior = fe->spch[len - 1];
<a name="l00581"></a>00581 }
<a name="l00582"></a>00582 <span class="keywordflow">else</span>
<a name="l00583"></a>00583 fe_short_to_frame(fe->spch, fe->frame, len);
<a name="l00584"></a>00584
<a name="l00585"></a>00585 <span class="comment">/* Zero pad up to FFT size. */</span>
<a name="l00586"></a>00586 memset(fe->frame + len, 0,
<a name="l00587"></a>00587 (fe->fft_size - len) * <span class="keyword">sizeof</span>(*fe->frame));
<a name="l00588"></a>00588
<a name="l00589"></a>00589 <span class="comment">/* Window. */</span>
<a name="l00590"></a>00590 fe_hamming_window(fe->frame, fe->hamming_window, fe->frame_size,
<a name="l00591"></a>00591 fe->remove_dc);
<a name="l00592"></a>00592
<a name="l00593"></a>00593 <span class="keywordflow">return</span> len;
<a name="l00594"></a>00594 }
<a name="l00595"></a>00595
<a name="l00596"></a>00596 <span class="keywordtype">int</span>
<a name="l00597"></a>00597 fe_read_frame(<a class="code" href="structfe__s.html" title="Structure for the front-end computation.">fe_t</a> *fe, int16 <span class="keyword">const</span> *in, int32 len)
<a name="l00598"></a>00598 {
<a name="l00599"></a>00599 <span class="keywordtype">int</span> i;
<a name="l00600"></a>00600
<a name="l00601"></a>00601 <span class="keywordflow">if</span> (len > fe->frame_size)
<a name="l00602"></a>00602 len = fe->frame_size;
<a name="l00603"></a>00603
<a name="l00604"></a>00604 <span class="comment">/* Read it into the raw speech buffer. */</span>
<a name="l00605"></a>00605 memcpy(fe->spch, in, len * <span class="keyword">sizeof</span>(*in));
<a name="l00606"></a>00606 <span class="comment">/* Swap and dither if necessary. */</span>
<a name="l00607"></a>00607 <span class="keywordflow">if</span> (fe->swap)
<a name="l00608"></a>00608 <span class="keywordflow">for</span> (i = 0; i < len; ++i)
<a name="l00609"></a>00609 SWAP_INT16(&fe->spch[i]);
<a name="l00610"></a>00610 <span class="keywordflow">if</span> (fe->dither)
<a name="l00611"></a>00611 <span class="keywordflow">for</span> (i = 0; i < len; ++i)
<a name="l00612"></a>00612 fe->spch[i] += (int16) ((!(s3_rand_int31() % 4)) ? 1 : 0);
<a name="l00613"></a>00613
<a name="l00614"></a>00614 <span class="keywordflow">return</span> fe_spch_to_frame(fe, len);
<a name="l00615"></a>00615 }
<a name="l00616"></a>00616
<a name="l00617"></a>00617 <span class="keywordtype">int</span>
<a name="l00618"></a>00618 fe_shift_frame(<a class="code" href="structfe__s.html" title="Structure for the front-end computation.">fe_t</a> *fe, int16 <span class="keyword">const</span> *in, int32 len)
<a name="l00619"></a>00619 {
<a name="l00620"></a>00620 <span class="keywordtype">int</span> offset, i;
<a name="l00621"></a>00621
<a name="l00622"></a>00622 <span class="keywordflow">if</span> (len > fe->frame_shift)
<a name="l00623"></a>00623 len = fe->frame_shift;
<a name="l00624"></a>00624 offset = fe->frame_size - fe->frame_shift;
<a name="l00625"></a>00625
<a name="l00626"></a>00626 <span class="comment">/* Shift data into the raw speech buffer. */</span>
<a name="l00627"></a>00627 memmove(fe->spch, fe->spch + fe->frame_shift,
<a name="l00628"></a>00628 offset * <span class="keyword">sizeof</span>(*fe->spch));
<a name="l00629"></a>00629 memcpy(fe->spch + offset, in, len * <span class="keyword">sizeof</span>(*fe->spch));
<a name="l00630"></a>00630 <span class="comment">/* Swap and dither if necessary. */</span>
<a name="l00631"></a>00631 <span class="keywordflow">if</span> (fe->swap)
<a name="l00632"></a>00632 <span class="keywordflow">for</span> (i = 0; i < len; ++i)
<a name="l00633"></a>00633 SWAP_INT16(&fe->spch[offset + i]);
<a name="l00634"></a>00634 <span class="keywordflow">if</span> (fe->dither)
<a name="l00635"></a>00635 <span class="keywordflow">for</span> (i = 0; i < len; ++i)
<a name="l00636"></a>00636 fe->spch[offset + i]
<a name="l00637"></a>00637 += (int16) ((!(s3_rand_int31() % 4)) ? 1 : 0);
<a name="l00638"></a>00638
<a name="l00639"></a>00639 <span class="keywordflow">return</span> fe_spch_to_frame(fe, offset + len);
<a name="l00640"></a>00640 }
<a name="l00641"></a>00641
<a name="l00645"></a>00645 <span class="keywordtype">void</span>
<a name="l00646"></a>00646 fe_create_twiddle(<a class="code" href="structfe__s.html" title="Structure for the front-end computation.">fe_t</a> *fe)
<a name="l00647"></a>00647 {
<a name="l00648"></a>00648 <span class="keywordtype">int</span> i;
<a name="l00649"></a>00649
<a name="l00650"></a>00650 <span class="keywordflow">for</span> (i = 0; i < fe->fft_size / 4; ++i) {
<a name="l00651"></a>00651 float64 a = 2 * M_PI * i / fe->fft_size;
<a name="l00652"></a>00652 <span class="preprocessor">#ifdef FIXED16</span>
<a name="l00653"></a>00653 <span class="preprocessor"></span> fe->ccc[i] = (int16)(cos(a) * 0x8000);
<a name="l00654"></a>00654 fe->sss[i] = (int16)(sin(a) * 0x8000);
<a name="l00655"></a>00655 <span class="preprocessor">#elif defined(FIXED_POINT)</span>
<a name="l00656"></a>00656 <span class="preprocessor"></span> fe->ccc[i] = FLOAT2COS(cos(a));
<a name="l00657"></a>00657 fe->sss[i] = FLOAT2COS(sin(a));
<a name="l00658"></a>00658 <span class="preprocessor">#else</span>
<a name="l00659"></a>00659 <span class="preprocessor"></span> fe->ccc[i] = cos(a);
<a name="l00660"></a>00660 fe->sss[i] = sin(a);
<a name="l00661"></a>00661 <span class="preprocessor">#endif</span>
<a name="l00662"></a>00662 <span class="preprocessor"></span> }
<a name="l00663"></a>00663 }
<a name="l00664"></a>00664
<a name="l00665"></a>00665 <span class="comment">/* Translated from the FORTRAN (obviously) from "Real-Valued Fast</span>
<a name="l00666"></a>00666 <span class="comment"> * Fourier Transform Algorithms" by Henrik V. Sorensen et al., IEEE</span>
<a name="l00667"></a>00667 <span class="comment"> * Transactions on Acoustics, Speech, and Signal Processing, vol. 35,</span>
<a name="l00668"></a>00668 <span class="comment"> * no.6. The 16-bit version does a version of "block floating</span>
<a name="l00669"></a>00669 <span class="comment"> * point" in order to avoid rounding errors.</span>
<a name="l00670"></a>00670 <span class="comment"> */</span>
<a name="l00671"></a>00671 <span class="preprocessor">#if defined(FIXED16)</span>
<a name="l00672"></a>00672 <span class="preprocessor"></span><span class="keyword">static</span> <span class="keywordtype">int</span>
<a name="l00673"></a>00673 fe_fft_real(<a class="code" href="structfe__s.html" title="Structure for the front-end computation.">fe_t</a> *fe)
<a name="l00674"></a>00674 {
<a name="l00675"></a>00675 <span class="keywordtype">int</span> i, j, k, m, n, lz;
<a name="l00676"></a>00676 frame_t *x, xt, max;
<a name="l00677"></a>00677
<a name="l00678"></a>00678 x = fe->frame;
<a name="l00679"></a>00679 m = fe->fft_order;
<a name="l00680"></a>00680 n = fe->fft_size;
<a name="l00681"></a>00681
<a name="l00682"></a>00682 <span class="comment">/* Bit-reverse the input. */</span>
<a name="l00683"></a>00683 j = 0;
<a name="l00684"></a>00684 <span class="keywordflow">for</span> (i = 0; i < n - 1; ++i) {
<a name="l00685"></a>00685 <span class="keywordflow">if</span> (i < j) {
<a name="l00686"></a>00686 xt = x[j];
<a name="l00687"></a>00687 x[j] = x[i];
<a name="l00688"></a>00688 x[i] = xt;
<a name="l00689"></a>00689 }
<a name="l00690"></a>00690 k = n / 2;
<a name="l00691"></a>00691 <span class="keywordflow">while</span> (k <= j) {
<a name="l00692"></a>00692 j -= k;
<a name="l00693"></a>00693 k /= 2;
<a name="l00694"></a>00694 }
<a name="l00695"></a>00695 j += k;
<a name="l00696"></a>00696 }
<a name="l00697"></a>00697 <span class="comment">/* Determine how many bits of dynamic range are in the input. */</span>
<a name="l00698"></a>00698 max = 0;
<a name="l00699"></a>00699 <span class="keywordflow">for</span> (i = 0; i < n; ++i)
<a name="l00700"></a>00700 <span class="keywordflow">if</span> (abs(x[i]) > max)
<a name="l00701"></a>00701 max = abs(x[i]);
<a name="l00702"></a>00702 <span class="comment">/* The FFT has a gain of M bits, so we need to attenuate the input</span>
<a name="l00703"></a>00703 <span class="comment"> * by M bits minus the number of leading zeroes in the input's</span>
<a name="l00704"></a>00704 <span class="comment"> * range in order to avoid overflows. */</span>
<a name="l00705"></a>00705 <span class="keywordflow">for</span> (lz = 0; lz < m; ++lz)
<a name="l00706"></a>00706 <span class="keywordflow">if</span> (max & (1 << (15-lz)))
<a name="l00707"></a>00707 <span class="keywordflow">break</span>;
<a name="l00708"></a>00708
<a name="l00709"></a>00709 <span class="comment">/* Basic butterflies (2-point FFT, real twiddle factors):</span>
<a name="l00710"></a>00710 <span class="comment"> * x[i] = x[i] + 1 * x[i+1]</span>
<a name="l00711"></a>00711 <span class="comment"> * x[i+1] = x[i] + -1 * x[i+1]</span>
<a name="l00712"></a>00712 <span class="comment"> */</span>
<a name="l00713"></a>00713 <span class="comment">/* The quantization error introduced by attenuating the input at</span>
<a name="l00714"></a>00714 <span class="comment"> * any given stage of the FFT has a cascading effect, so we hold</span>
<a name="l00715"></a>00715 <span class="comment"> * off on it until it's absolutely necessary. */</span>
<a name="l00716"></a>00716 <span class="keywordflow">for</span> (i = 0; i < n; i += 2) {
<a name="l00717"></a>00717 <span class="keywordtype">int</span> atten = (lz == 0);
<a name="l00718"></a>00718 xt = x[i] >> atten;
<a name="l00719"></a>00719 x[i] = xt + (x[i + 1] >> atten);
<a name="l00720"></a>00720 x[i + 1] = xt - (x[i + 1] >> atten);
<a name="l00721"></a>00721 }
<a name="l00722"></a>00722
<a name="l00723"></a>00723 <span class="comment">/* The rest of the butterflies, in stages from 1..m */</span>
<a name="l00724"></a>00724 <span class="keywordflow">for</span> (k = 1; k < m; ++k) {
<a name="l00725"></a>00725 <span class="keywordtype">int</span> n1, n2, n4;
<a name="l00726"></a>00726 <span class="comment">/* Start attenuating once we hit the number of leading zeros. */</span>
<a name="l00727"></a>00727 <span class="keywordtype">int</span> atten = (k >= lz);
<a name="l00728"></a>00728
<a name="l00729"></a>00729 n4 = k - 1;
<a name="l00730"></a>00730 n2 = k;
<a name="l00731"></a>00731 n1 = k + 1;
<a name="l00732"></a>00732 <span class="comment">/* Stride over each (1 << (k+1)) points */</span>
<a name="l00733"></a>00733 <span class="keywordflow">for</span> (i = 0; i < n; i += (1 << n1)) {
<a name="l00734"></a>00734 <span class="comment">/* Basic butterfly with real twiddle factors:</span>
<a name="l00735"></a>00735 <span class="comment"> * x[i] = x[i] + 1 * x[i + (1<<k)]</span>
<a name="l00736"></a>00736 <span class="comment"> * x[i + (1<<k)] = x[i] + -1 * x[i + (1<<k)]</span>
<a name="l00737"></a>00737 <span class="comment"> */</span>
<a name="l00738"></a>00738 xt = x[i] >> atten;
<a name="l00739"></a>00739 x[i] = xt + (x[i + (1 << n2)] >> atten);
<a name="l00740"></a>00740 x[i + (1 << n2)] = xt - (x[i + (1 << n2)] >> atten);
<a name="l00741"></a>00741
<a name="l00742"></a>00742 <span class="comment">/* The other ones with real twiddle factors:</span>
<a name="l00743"></a>00743 <span class="comment"> * x[i + (1<<k) + (1<<(k-1))]</span>
<a name="l00744"></a>00744 <span class="comment"> * = 0 * x[i + (1<<k-1)] + -1 * x[i + (1<<k) + (1<<k-1)]</span>
<a name="l00745"></a>00745 <span class="comment"> * x[i + (1<<(k-1))]</span>
<a name="l00746"></a>00746 <span class="comment"> * = 1 * x[i + (1<<k-1)] + 0 * x[i + (1<<k) + (1<<k-1)]</span>
<a name="l00747"></a>00747 <span class="comment"> */</span>
<a name="l00748"></a>00748 x[i + (1 << n2) + (1 << n4)] = -x[i + (1 << n2) + (1 << n4)] >> atten;
<a name="l00749"></a>00749 x[i + (1 << n4)] = x[i + (1 << n4)] >> atten;
<a name="l00750"></a>00750
<a name="l00751"></a>00751 <span class="comment">/* Butterflies with complex twiddle factors.</span>
<a name="l00752"></a>00752 <span class="comment"> * There are (1<<k-1) of them.</span>
<a name="l00753"></a>00753 <span class="comment"> */</span>
<a name="l00754"></a>00754 <span class="keywordflow">for</span> (j = 1; j < (1 << n4); ++j) {
<a name="l00755"></a>00755 frame_t cc, ss, t1, t2;
<a name="l00756"></a>00756 <span class="keywordtype">int</span> i1, i2, i3, i4;
<a name="l00757"></a>00757
<a name="l00758"></a>00758 i1 = i + j;
<a name="l00759"></a>00759 i2 = i + (1 << n2) - j;
<a name="l00760"></a>00760 i3 = i + (1 << n2) + j;
<a name="l00761"></a>00761 i4 = i + (1 << n2) + (1 << n2) - j;
<a name="l00762"></a>00762
<a name="l00763"></a>00763 <span class="comment">/*</span>
<a name="l00764"></a>00764 <span class="comment"> * cc = real(W[j * n / (1<<(k+1))])</span>
<a name="l00765"></a>00765 <span class="comment"> * ss = imag(W[j * n / (1<<(k+1))])</span>
<a name="l00766"></a>00766 <span class="comment"> */</span>
<a name="l00767"></a>00767 cc = fe->ccc[j << (m - n1)];
<a name="l00768"></a>00768 ss = fe->sss[j << (m - n1)];
<a name="l00769"></a>00769
<a name="l00770"></a>00770 <span class="comment">/* There are some symmetry properties which allow us</span>
<a name="l00771"></a>00771 <span class="comment"> * to get away with only four multiplications here. */</span>
<a name="l00772"></a>00772 {
<a name="l00773"></a>00773 int32 tmp1, tmp2;
<a name="l00774"></a>00774 tmp1 = (int32)x[i3] * cc + (int32)x[i4] * ss;
<a name="l00775"></a>00775 tmp2 = (int32)x[i3] * ss - (int32)x[i4] * cc;
<a name="l00776"></a>00776 t1 = (int16)(tmp1 >> 15) >> atten;
<a name="l00777"></a>00777 t2 = (int16)(tmp2 >> 15) >> atten;
<a name="l00778"></a>00778 }
<a name="l00779"></a>00779
<a name="l00780"></a>00780 x[i4] = (x[i2] >> atten) - t2;
<a name="l00781"></a>00781 x[i3] = (-x[i2] >> atten) - t2;
<a name="l00782"></a>00782 x[i2] = (x[i1] >> atten) - t1;
<a name="l00783"></a>00783 x[i1] = (x[i1] >> atten) + t1;
<a name="l00784"></a>00784 }
<a name="l00785"></a>00785 }
<a name="l00786"></a>00786 }
<a name="l00787"></a>00787
<a name="l00788"></a>00788 <span class="comment">/* Return the residual scaling factor. */</span>
<a name="l00789"></a>00789 <span class="keywordflow">return</span> lz;
<a name="l00790"></a>00790 }
<a name="l00791"></a>00791 <span class="preprocessor">#else </span><span class="comment">/* !FIXED16 */</span>
<a name="l00792"></a>00792 <span class="keyword">static</span> <span class="keywordtype">int</span>
<a name="l00793"></a>00793 fe_fft_real(<a class="code" href="structfe__s.html" title="Structure for the front-end computation.">fe_t</a> *fe)
<a name="l00794"></a>00794 {
<a name="l00795"></a>00795 <span class="keywordtype">int</span> i, j, k, m, n;
<a name="l00796"></a>00796 frame_t *x, xt;
<a name="l00797"></a>00797
<a name="l00798"></a>00798 x = fe->frame;
<a name="l00799"></a>00799 m = fe->fft_order;
<a name="l00800"></a>00800 n = fe->fft_size;
<a name="l00801"></a>00801
<a name="l00802"></a>00802 <span class="comment">/* Bit-reverse the input. */</span>
<a name="l00803"></a>00803 j = 0;
<a name="l00804"></a>00804 <span class="keywordflow">for</span> (i = 0; i < n - 1; ++i) {
<a name="l00805"></a>00805 <span class="keywordflow">if</span> (i < j) {
<a name="l00806"></a>00806 xt = x[j];
<a name="l00807"></a>00807 x[j] = x[i];
<a name="l00808"></a>00808 x[i] = xt;
<a name="l00809"></a>00809 }
<a name="l00810"></a>00810 k = n / 2;
<a name="l00811"></a>00811 <span class="keywordflow">while</span> (k <= j) {
<a name="l00812"></a>00812 j -= k;
<a name="l00813"></a>00813 k /= 2;
<a name="l00814"></a>00814 }
<a name="l00815"></a>00815 j += k;
<a name="l00816"></a>00816 }
<a name="l00817"></a>00817
<a name="l00818"></a>00818 <span class="comment">/* Basic butterflies (2-point FFT, real twiddle factors):</span>
<a name="l00819"></a>00819 <span class="comment"> * x[i] = x[i] + 1 * x[i+1]</span>
<a name="l00820"></a>00820 <span class="comment"> * x[i+1] = x[i] + -1 * x[i+1]</span>
<a name="l00821"></a>00821 <span class="comment"> */</span>
<a name="l00822"></a>00822 <span class="keywordflow">for</span> (i = 0; i < n; i += 2) {
<a name="l00823"></a>00823 xt = x[i];
<a name="l00824"></a>00824 x[i] = (xt + x[i + 1]);
<a name="l00825"></a>00825 x[i + 1] = (xt - x[i + 1]);
<a name="l00826"></a>00826 }
<a name="l00827"></a>00827
<a name="l00828"></a>00828 <span class="comment">/* The rest of the butterflies, in stages from 1..m */</span>
<a name="l00829"></a>00829 <span class="keywordflow">for</span> (k = 1; k < m; ++k) {
<a name="l00830"></a>00830 <span class="keywordtype">int</span> n1, n2, n4;
<a name="l00831"></a>00831
<a name="l00832"></a>00832 n4 = k - 1;
<a name="l00833"></a>00833 n2 = k;
<a name="l00834"></a>00834 n1 = k + 1;
<a name="l00835"></a>00835 <span class="comment">/* Stride over each (1 << (k+1)) points */</span>
<a name="l00836"></a>00836 <span class="keywordflow">for</span> (i = 0; i < n; i += (1 << n1)) {
<a name="l00837"></a>00837 <span class="comment">/* Basic butterfly with real twiddle factors:</span>
<a name="l00838"></a>00838 <span class="comment"> * x[i] = x[i] + 1 * x[i + (1<<k)]</span>
<a name="l00839"></a>00839 <span class="comment"> * x[i + (1<<k)] = x[i] + -1 * x[i + (1<<k)]</span>
<a name="l00840"></a>00840 <span class="comment"> */</span>
<a name="l00841"></a>00841 xt = x[i];
<a name="l00842"></a>00842 x[i] = (xt + x[i + (1 << n2)]);
<a name="l00843"></a>00843 x[i + (1 << n2)] = (xt - x[i + (1 << n2)]);
<a name="l00844"></a>00844
<a name="l00845"></a>00845 <span class="comment">/* The other ones with real twiddle factors:</span>
<a name="l00846"></a>00846 <span class="comment"> * x[i + (1<<k) + (1<<(k-1))]</span>
<a name="l00847"></a>00847 <span class="comment"> * = 0 * x[i + (1<<k-1)] + -1 * x[i + (1<<k) + (1<<k-1)]</span>
<a name="l00848"></a>00848 <span class="comment"> * x[i + (1<<(k-1))]</span>
<a name="l00849"></a>00849 <span class="comment"> * = 1 * x[i + (1<<k-1)] + 0 * x[i + (1<<k) + (1<<k-1)]</span>
<a name="l00850"></a>00850 <span class="comment"> */</span>
<a name="l00851"></a>00851 x[i + (1 << n2) + (1 << n4)] = -x[i + (1 << n2) + (1 << n4)];
<a name="l00852"></a>00852 x[i + (1 << n4)] = x[i + (1 << n4)];
<a name="l00853"></a>00853
<a name="l00854"></a>00854 <span class="comment">/* Butterflies with complex twiddle factors.</span>
<a name="l00855"></a>00855 <span class="comment"> * There are (1<<k-1) of them.</span>
<a name="l00856"></a>00856 <span class="comment"> */</span>
<a name="l00857"></a>00857 <span class="keywordflow">for</span> (j = 1; j < (1 << n4); ++j) {
<a name="l00858"></a>00858 frame_t cc, ss, t1, t2;
<a name="l00859"></a>00859 <span class="keywordtype">int</span> i1, i2, i3, i4;
<a name="l00860"></a>00860
<a name="l00861"></a>00861 i1 = i + j;
<a name="l00862"></a>00862 i2 = i + (1 << n2) - j;
<a name="l00863"></a>00863 i3 = i + (1 << n2) + j;
<a name="l00864"></a>00864 i4 = i + (1 << n2) + (1 << n2) - j;
<a name="l00865"></a>00865
<a name="l00866"></a>00866 <span class="comment">/*</span>
<a name="l00867"></a>00867 <span class="comment"> * cc = real(W[j * n / (1<<(k+1))])</span>
<a name="l00868"></a>00868 <span class="comment"> * ss = imag(W[j * n / (1<<(k+1))])</span>
<a name="l00869"></a>00869 <span class="comment"> */</span>
<a name="l00870"></a>00870 cc = fe->ccc[j << (m - n1)];
<a name="l00871"></a>00871 ss = fe->sss[j << (m - n1)];
<a name="l00872"></a>00872
<a name="l00873"></a>00873 <span class="comment">/* There are some symmetry properties which allow us</span>
<a name="l00874"></a>00874 <span class="comment"> * to get away with only four multiplications here. */</span>
<a name="l00875"></a>00875 t1 = COSMUL(x[i3], cc) + COSMUL(x[i4], ss);
<a name="l00876"></a>00876 t2 = COSMUL(x[i3], ss) - COSMUL(x[i4], cc);
<a name="l00877"></a>00877
<a name="l00878"></a>00878 x[i4] = (x[i2] - t2);
<a name="l00879"></a>00879 x[i3] = (-x[i2] - t2);
<a name="l00880"></a>00880 x[i2] = (x[i1] - t1);
<a name="l00881"></a>00881 x[i1] = (x[i1] + t1);
<a name="l00882"></a>00882 }
<a name="l00883"></a>00883 }
<a name="l00884"></a>00884 }
<a name="l00885"></a>00885
<a name="l00886"></a>00886 <span class="comment">/* This isn't used, but return it for completeness. */</span>
<a name="l00887"></a>00887 <span class="keywordflow">return</span> m;
<a name="l00888"></a>00888 }
<a name="l00889"></a>00889 <span class="preprocessor">#endif </span><span class="comment">/* !FIXED16 */</span>
<a name="l00890"></a>00890
<a name="l00891"></a>00891 <span class="keyword">static</span> <span class="keywordtype">void</span>
<a name="l00892"></a>00892 fe_spec_magnitude(<a class="code" href="structfe__s.html" title="Structure for the front-end computation.">fe_t</a> *fe)
<a name="l00893"></a>00893 {
<a name="l00894"></a>00894 frame_t *fft;
<a name="l00895"></a>00895 powspec_t *spec;
<a name="l00896"></a>00896 int32 j, scale, fftsize;
<a name="l00897"></a>00897
<a name="l00898"></a>00898 <span class="comment">/* Do FFT and get the scaling factor back (only actually used in</span>
<a name="l00899"></a>00899 <span class="comment"> * fixed-point). Note the scaling factor is expressed in bits. */</span>
<a name="l00900"></a>00900 scale = fe_fft_real(fe);
<a name="l00901"></a>00901
<a name="l00902"></a>00902 <span class="comment">/* Convenience pointers to make things less awkward below. */</span>
<a name="l00903"></a>00903 fft = fe->frame;
<a name="l00904"></a>00904 spec = fe->spec;
<a name="l00905"></a>00905 fftsize = fe->fft_size;
<a name="l00906"></a>00906
<a name="l00907"></a>00907 <span class="comment">/* We need to scale things up the rest of the way to N. */</span>
<a name="l00908"></a>00908 scale = fe->fft_order - scale;
<a name="l00909"></a>00909
<a name="l00910"></a>00910 <span class="comment">/* The first point (DC coefficient) has no imaginary part */</span>
<a name="l00911"></a>00911 {
<a name="l00912"></a>00912 <span class="preprocessor">#ifdef FIXED16</span>
<a name="l00913"></a>00913 <span class="preprocessor"></span> spec[0] = fixlog(abs(fft[0]) << scale) * 2;
<a name="l00914"></a>00914 <span class="preprocessor">#elif defined(FIXED_POINT)</span>
<a name="l00915"></a>00915 <span class="preprocessor"></span> spec[0] = FIXLN(abs(fft[0]) << scale) * 2;
<a name="l00916"></a>00916 <span class="preprocessor">#else</span>
<a name="l00917"></a>00917 <span class="preprocessor"></span> spec[0] = fft[0] * fft[0];
<a name="l00918"></a>00918 <span class="preprocessor">#endif</span>
<a name="l00919"></a>00919 <span class="preprocessor"></span> }
<a name="l00920"></a>00920
<a name="l00921"></a>00921 <span class="keywordflow">for</span> (j = 1; j <= fftsize / 2; j++) {
<a name="l00922"></a>00922 <span class="preprocessor">#ifdef FIXED16</span>
<a name="l00923"></a>00923 <span class="preprocessor"></span> int32 rr = fixlog(abs(fft[j]) << scale) * 2;
<a name="l00924"></a>00924 int32 ii = fixlog(abs(fft[fftsize - j]) << scale) * 2;
<a name="l00925"></a>00925 spec[j] = fe_log_add(rr, ii);
<a name="l00926"></a>00926 <span class="preprocessor">#elif defined(FIXED_POINT)</span>
<a name="l00927"></a>00927 <span class="preprocessor"></span> int32 rr = FIXLN(abs(fft[j]) << scale) * 2;
<a name="l00928"></a>00928 int32 ii = FIXLN(abs(fft[fftsize - j]) << scale) * 2;
<a name="l00929"></a>00929 spec[j] = fe_log_add(rr, ii);
<a name="l00930"></a>00930 <span class="preprocessor">#else</span>
<a name="l00931"></a>00931 <span class="preprocessor"></span> spec[j] = fft[j] * fft[j] + fft[fftsize - j] * fft[fftsize - j];
<a name="l00932"></a>00932 <span class="preprocessor">#endif</span>
<a name="l00933"></a>00933 <span class="preprocessor"></span> }
<a name="l00934"></a>00934 }
<a name="l00935"></a>00935
<a name="l00936"></a>00936 <span class="keyword">static</span> <span class="keywordtype">void</span>
<a name="l00937"></a>00937 fe_mel_spec(<a class="code" href="structfe__s.html" title="Structure for the front-end computation.">fe_t</a> * fe)
<a name="l00938"></a>00938 {
<a name="l00939"></a>00939 <span class="keywordtype">int</span> whichfilt;
<a name="l00940"></a>00940 powspec_t *spec, *mfspec;
<a name="l00941"></a>00941
<a name="l00942"></a>00942 <span class="comment">/* Convenience poitners. */</span>
<a name="l00943"></a>00943 spec = fe->spec;
<a name="l00944"></a>00944 mfspec = fe->mfspec;
<a name="l00945"></a>00945
<a name="l00946"></a>00946 <span class="keywordflow">for</span> (whichfilt = 0; whichfilt < fe->mel_fb->num_filters; whichfilt++) {
<a name="l00947"></a>00947 <span class="keywordtype">int</span> spec_start, filt_start, i;
<a name="l00948"></a>00948
<a name="l00949"></a>00949 spec_start = fe->mel_fb->spec_start[whichfilt];
<a name="l00950"></a>00950 filt_start = fe->mel_fb->filt_start[whichfilt];
<a name="l00951"></a>00951
<a name="l00952"></a>00952 <span class="preprocessor">#ifdef FIXED_POINT</span>
<a name="l00953"></a>00953 <span class="preprocessor"></span> mfspec[whichfilt] = spec[spec_start] + fe->mel_fb->filt_coeffs[filt_start];
<a name="l00954"></a>00954 <span class="keywordflow">for</span> (i = 1; i < fe->mel_fb->filt_width[whichfilt]; i++) {
<a name="l00955"></a>00955 mfspec[whichfilt] = fe_log_add(mfspec[whichfilt],
<a name="l00956"></a>00956 spec[spec_start + i] +
<a name="l00957"></a>00957 fe->mel_fb->filt_coeffs[filt_start + i]);
<a name="l00958"></a>00958 }
<a name="l00959"></a>00959 <span class="preprocessor">#else </span><span class="comment">/* !FIXED_POINT */</span>
<a name="l00960"></a>00960 mfspec[whichfilt] = 0;
<a name="l00961"></a>00961 <span class="keywordflow">for</span> (i = 0; i < fe->mel_fb->filt_width[whichfilt]; i++)
<a name="l00962"></a>00962 mfspec[whichfilt] +=
<a name="l00963"></a>00963 spec[spec_start + i] * fe->mel_fb->filt_coeffs[filt_start + i];
<a name="l00964"></a>00964 #endif <span class="comment">/* !FIXED_POINT */</span>
<a name="l00965"></a>00965 }
<a name="l00966"></a>00966 }
<a name="l00967"></a>00967
<a name="l00968"></a>00968 <span class="keyword">static</span> <span class="keywordtype">void</span>
<a name="l00969"></a>00969 fe_mel_cep(<a class="code" href="structfe__s.html" title="Structure for the front-end computation.">fe_t</a> * fe, mfcc_t *mfcep)
<a name="l00970"></a>00970 {
<a name="l00971"></a>00971 int32 i;
<a name="l00972"></a>00972 powspec_t *mfspec;
<a name="l00973"></a>00973
<a name="l00974"></a>00974 <span class="comment">/* Convenience pointer. */</span>
<a name="l00975"></a>00975 mfspec = fe->mfspec;
<a name="l00976"></a>00976
<a name="l00977"></a>00977 <span class="keywordflow">for</span> (i = 0; i < fe->mel_fb->num_filters; ++i) {
<a name="l00978"></a>00978 <span class="preprocessor">#ifndef FIXED_POINT </span><span class="comment">/* It's already in log domain for fixed point */</span>
<a name="l00979"></a>00979 <span class="keywordflow">if</span> (mfspec[i] > 0)
<a name="l00980"></a>00980 mfspec[i] = log(mfspec[i]);
<a name="l00981"></a>00981 <span class="keywordflow">else</span> <span class="comment">/* This number should be smaller than anything</span>
<a name="l00982"></a>00982 <span class="comment"> * else, but not too small, so as to avoid</span>
<a name="l00983"></a>00983 <span class="comment"> * infinities in the inverse transform (this is</span>
<a name="l00984"></a>00984 <span class="comment"> * the frequency-domain equivalent of</span>
<a name="l00985"></a>00985 <span class="comment"> * dithering) */</span>
<a name="l00986"></a>00986 mfspec[i] = -10.0;
<a name="l00987"></a>00987 <span class="preprocessor">#endif </span><span class="comment">/* !FIXED_POINT */</span>
<a name="l00988"></a>00988 }
<a name="l00989"></a>00989
<a name="l00990"></a>00990 <span class="comment">/* If we are doing LOG_SPEC, then do nothing. */</span>
<a name="l00991"></a>00991 <span class="keywordflow">if</span> (fe->log_spec == RAW_LOG_SPEC) {
<a name="l00992"></a>00992 <span class="keywordflow">for</span> (i = 0; i < fe->feature_dimension; i++) {
<a name="l00993"></a>00993 mfcep[i] = (mfcc_t) mfspec[i];
<a name="l00994"></a>00994 }
<a name="l00995"></a>00995 }
<a name="l00996"></a>00996 <span class="comment">/* For smoothed spectrum, do DCT-II followed by (its inverse) DCT-III */</span>
<a name="l00997"></a>00997 <span class="keywordflow">else</span> <span class="keywordflow">if</span> (fe->log_spec == SMOOTH_LOG_SPEC) {
<a name="l00998"></a>00998 <span class="comment">/* FIXME: This is probably broken for fixed-point. */</span>
<a name="l00999"></a>00999 fe_dct2(fe, mfspec, mfcep, 0);
<a name="l01000"></a>01000 fe_dct3(fe, mfcep, mfspec);
<a name="l01001"></a>01001 <span class="keywordflow">for</span> (i = 0; i < fe->feature_dimension; i++) {
<a name="l01002"></a>01002 mfcep[i] = (mfcc_t) mfspec[i];
<a name="l01003"></a>01003 }
<a name="l01004"></a>01004 }
<a name="l01005"></a>01005 <span class="keywordflow">else</span> <span class="keywordflow">if</span> (fe->transform == DCT_II)
<a name="l01006"></a>01006 fe_dct2(fe, mfspec, mfcep, FALSE);
<a name="l01007"></a>01007 <span class="keywordflow">else</span> <span class="keywordflow">if</span> (fe->transform == DCT_HTK)
<a name="l01008"></a>01008 fe_dct2(fe, mfspec, mfcep, TRUE);
<a name="l01009"></a>01009 <span class="keywordflow">else</span>
<a name="l01010"></a>01010 fe_spec2cep(fe, mfspec, mfcep);
<a name="l01011"></a>01011
<a name="l01012"></a>01012 <span class="keywordflow">return</span>;
<a name="l01013"></a>01013 }
<a name="l01014"></a>01014
<a name="l01015"></a>01015 <span class="keywordtype">void</span>
<a name="l01016"></a>01016 fe_spec2cep(<a class="code" href="structfe__s.html" title="Structure for the front-end computation.">fe_t</a> * fe, <span class="keyword">const</span> powspec_t * mflogspec, mfcc_t * mfcep)
<a name="l01017"></a>01017 {
<a name="l01018"></a>01018 int32 i, j, beta;
<a name="l01019"></a>01019
<a name="l01020"></a>01020 <span class="comment">/* Compute C0 separately (its basis vector is 1) to avoid</span>
<a name="l01021"></a>01021 <span class="comment"> * costly multiplications. */</span>
<a name="l01022"></a>01022 mfcep[0] = mflogspec[0] / 2; <span class="comment">/* beta = 0.5 */</span>
<a name="l01023"></a>01023 <span class="keywordflow">for</span> (j = 1; j < fe->mel_fb->num_filters; j++)
<a name="l01024"></a>01024 mfcep[0] += mflogspec[j]; <span class="comment">/* beta = 1.0 */</span>
<a name="l01025"></a>01025 mfcep[0] /= (frame_t) fe->mel_fb->num_filters;
<a name="l01026"></a>01026
<a name="l01027"></a>01027 for (i = 1; i < fe->num_cepstra; ++i) {
<a name="l01028"></a>01028 mfcep[i] = 0;
<a name="l01029"></a>01029 <span class="keywordflow">for</span> (j = 0; j < fe->mel_fb->num_filters; j++) {
<a name="l01030"></a>01030 <span class="keywordflow">if</span> (j == 0)
<a name="l01031"></a>01031 beta = 1; <span class="comment">/* 0.5 */</span>
<a name="l01032"></a>01032 <span class="keywordflow">else</span>
<a name="l01033"></a>01033 beta = 2; <span class="comment">/* 1.0 */</span>
<a name="l01034"></a>01034 mfcep[i] += COSMUL(mflogspec[j],
<a name="l01035"></a>01035 fe->mel_fb->mel_cosine[i][j]) * beta;
<a name="l01036"></a>01036 }
<a name="l01037"></a>01037 <span class="comment">/* Note that this actually normalizes by num_filters, like the</span>
<a name="l01038"></a>01038 <span class="comment"> * original Sphinx front-end, due to the doubled 'beta' factor</span>
<a name="l01039"></a>01039 <span class="comment"> * above. */</span>
<a name="l01040"></a>01040 mfcep[i] /= (frame_t) fe->mel_fb->num_filters * 2;
<a name="l01041"></a>01041 }
<a name="l01042"></a>01042 }
<a name="l01043"></a>01043
<a name="l01044"></a>01044 <span class="keywordtype">void</span>
<a name="l01045"></a>01045 fe_dct2(<a class="code" href="structfe__s.html" title="Structure for the front-end computation.">fe_t</a> * fe, <span class="keyword">const</span> powspec_t * mflogspec, mfcc_t * mfcep, <span class="keywordtype">int</span> htk)
<a name="l01046"></a>01046 {
<a name="l01047"></a>01047 int32 i, j;
<a name="l01048"></a>01048
<a name="l01049"></a>01049 <span class="comment">/* Compute C0 separately (its basis vector is 1) to avoid</span>
<a name="l01050"></a>01050 <span class="comment"> * costly multiplications. */</span>
<a name="l01051"></a>01051 mfcep[0] = mflogspec[0];
<a name="l01052"></a>01052 <span class="keywordflow">for</span> (j = 1; j < fe->mel_fb->num_filters; j++)
<a name="l01053"></a>01053 mfcep[0] += mflogspec[j];
<a name="l01054"></a>01054 <span class="keywordflow">if</span> (htk)
<a name="l01055"></a>01055 mfcep[0] = COSMUL(mfcep[0], fe->mel_fb->sqrt_inv_2n);
<a name="l01056"></a>01056 <span class="keywordflow">else</span> <span class="comment">/* sqrt(1/N) = sqrt(2/N) * 1/sqrt(2) */</span>
<a name="l01057"></a>01057 mfcep[0] = COSMUL(mfcep[0], fe->mel_fb->sqrt_inv_n);
<a name="l01058"></a>01058
<a name="l01059"></a>01059 <span class="keywordflow">for</span> (i = 1; i < fe->num_cepstra; ++i) {
<a name="l01060"></a>01060 mfcep[i] = 0;
<a name="l01061"></a>01061 <span class="keywordflow">for</span> (j = 0; j < fe->mel_fb->num_filters; j++) {
<a name="l01062"></a>01062 mfcep[i] += COSMUL(mflogspec[j],
<a name="l01063"></a>01063 fe->mel_fb->mel_cosine[i][j]);
<a name="l01064"></a>01064 }
<a name="l01065"></a>01065 mfcep[i] = COSMUL(mfcep[i], fe->mel_fb->sqrt_inv_2n);
<a name="l01066"></a>01066 }
<a name="l01067"></a>01067 }
<a name="l01068"></a>01068
<a name="l01069"></a>01069 <span class="keywordtype">void</span>
<a name="l01070"></a>01070 fe_lifter(<a class="code" href="structfe__s.html" title="Structure for the front-end computation.">fe_t</a> *fe, mfcc_t *mfcep)
<a name="l01071"></a>01071 {
<a name="l01072"></a>01072 int32 i;
<a name="l01073"></a>01073
<a name="l01074"></a>01074 <span class="keywordflow">if</span> (fe->mel_fb->lifter_val == 0)
<a name="l01075"></a>01075 <span class="keywordflow">return</span>;
<a name="l01076"></a>01076
<a name="l01077"></a>01077 <span class="keywordflow">for</span> (i = 0; i < fe->num_cepstra; ++i) {
<a name="l01078"></a>01078 mfcep[i] = MFCCMUL(mfcep[i], fe->mel_fb->lifter[i]);
<a name="l01079"></a>01079 }
<a name="l01080"></a>01080 }
<a name="l01081"></a>01081
<a name="l01082"></a>01082 <span class="keywordtype">void</span>
<a name="l01083"></a>01083 fe_dct3(<a class="code" href="structfe__s.html" title="Structure for the front-end computation.">fe_t</a> * fe, <span class="keyword">const</span> mfcc_t * mfcep, powspec_t * mflogspec)
<a name="l01084"></a>01084 {
<a name="l01085"></a>01085 int32 i, j;
<a name="l01086"></a>01086
<a name="l01087"></a>01087 <span class="keywordflow">for</span> (i = 0; i < fe->mel_fb->num_filters; ++i) {
<a name="l01088"></a>01088 mflogspec[i] = COSMUL(mfcep[0], SQRT_HALF);
<a name="l01089"></a>01089 <span class="keywordflow">for</span> (j = 1; j < fe->num_cepstra; j++) {
<a name="l01090"></a>01090 mflogspec[i] += COSMUL(mfcep[j],
<a name="l01091"></a>01091 fe->mel_fb->mel_cosine[j][i]);
<a name="l01092"></a>01092 }
<a name="l01093"></a>01093 mflogspec[i] = COSMUL(mflogspec[i], fe->mel_fb->sqrt_inv_2n);
<a name="l01094"></a>01094 }
<a name="l01095"></a>01095 }
<a name="l01096"></a>01096
<a name="l01097"></a>01097 int32
<a name="l01098"></a>01098 fe_write_frame(<a class="code" href="structfe__s.html" title="Structure for the front-end computation.">fe_t</a> * fe, mfcc_t * fea)
<a name="l01099"></a>01099 {
<a name="l01100"></a>01100 fe_spec_magnitude(fe);
<a name="l01101"></a>01101 fe_mel_spec(fe);
<a name="l01102"></a>01102 fe_mel_cep(fe, fea);
<a name="l01103"></a>01103 fe_lifter(fe, fea);
<a name="l01104"></a>01104
<a name="l01105"></a>01105 <span class="keywordflow">return</span> 1;
<a name="l01106"></a>01106 }
<a name="l01107"></a>01107
<a name="l01108"></a>01108 <span class="keywordtype">void</span> *
<a name="l01109"></a>01109 fe_create_2d(int32 d1, int32 d2, int32 elem_size)
<a name="l01110"></a>01110 {
<a name="l01111"></a>01111 <span class="keywordflow">return</span> (<span class="keywordtype">void</span> *)<a class="code" href="ckd__alloc_8h.html#a949e7b50fcd9697b1563fa57f50e9c4f" title="Macro for __ckd_calloc_2d__.">ckd_calloc_2d</a>(d1, d2, elem_size);
<a name="l01112"></a>01112 }
<a name="l01113"></a>01113
<a name="l01114"></a>01114 <span class="keywordtype">void</span>
<a name="l01115"></a>01115 fe_free_2d(<span class="keywordtype">void</span> *arr)
<a name="l01116"></a>01116 {
<a name="l01117"></a>01117 <a class="code" href="ckd__alloc_8h.html#a8246c071ac12e98b7e1df9fe6da15aef" title="Free a 2-D array (ptr) previously allocated by ckd_calloc_2d.">ckd_free_2d</a>((<span class="keywordtype">void</span> **)arr);
<a name="l01118"></a>01118 }
</pre></div></div>
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