86 lines
2.2 KiB
C
86 lines
2.2 KiB
C
/**
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@file pitch.c
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@brief Pitch analysis
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*/
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/* Copyright (C) 2005
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <stdio.h>
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#include <math.h>
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#include "fftwrap.h"
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#include "pitch.h"
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void find_spectral_pitch(void *fft, float *x, float *y, int lag, int len, int *pitch)
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{
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int n2 = lag/2;
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float xx[lag];
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float X[lag];
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float Y[lag];
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float curve[n2];
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int i;
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for (i=0;i<lag;i++)
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xx[i] = 0;
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for (i=0;i<len;i++)
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xx[i] = x[i];
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spx_fft(fft, xx, X);
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spx_fft(fft, y, Y);
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curve[0] = 1;
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for (i=1;i<n2;i++)
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{
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curve[i] = sqrt((X[2*i-1]*X[2*i-1] + X[2*i ]*X[2*i ])*(Y[2*i-1]*Y[2*i-1] + Y[2*i ]*Y[2*i ]));
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curve[i] = curve[i]+.7*curve[i];
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}
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for (i=n2-2;i>=0;i--)
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curve[i] = curve[i] + .7*curve[i+1];
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X[0] = 0;
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for (i=1;i<lag/2;i++)
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{
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float n;
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//n = 1.f/(1e1+sqrt(sqrt((X[2*i-1]*X[2*i-1] + X[2*i ]*X[2*i ])*(Y[2*i-1]*Y[2*i-1] + Y[2*i ]*Y[2*i ]))));
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//n = 1;
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n = 1.f/pow(1+curve[i],.8)/(i+60);
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//if (i>lag/6)
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// n *= .5;
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float tmp = X[2*i-1];
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X[2*i-1] = (X[2*i-1]*Y[2*i-1] + X[2*i ]*Y[2*i ])*n;
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X[2*i ] = (- X[2*i ]*Y[2*i-1] + tmp*Y[2*i ])*n;
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}
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X[lag-1] = 0;
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X[0] = X[lag-1] = 0;
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spx_ifft(fft, X, xx);
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float max_corr=-1e10;
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//int pitch;
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*pitch = 0;
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for (i=0;i<lag-len;i++)
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{
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//printf ("%f ", xx[i]);
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if (xx[i] > max_corr)
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{
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*pitch = i;
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max_corr = xx[i];
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}
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}
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//printf ("\n");
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//printf ("%d %f\n", *pitch, max_corr);
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//printf ("%d\n", *pitch);
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}
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