59 lines
1.9 KiB
C++
59 lines
1.9 KiB
C++
/*
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* Chromaprint -- Audio fingerprinting toolkit
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* Copyright (C) 2010 Lukas Lalinsky <lalinsky@gmail.com>
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*
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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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*
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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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*
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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 Street, Fifth Floor, Boston, MA 02110-1301
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* USA
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*/
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#include "utils.h"
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#include "fft_lib_fftw3.h"
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using namespace std;
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using namespace Chromaprint;
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FFTLib::FFTLib(int frame_size, double *window)
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: m_window(window),
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m_frame_size(frame_size)
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{
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m_input = (double *)fftw_malloc(sizeof(double) * frame_size);
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m_output = (double *)fftw_malloc(sizeof(double) * frame_size);
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m_plan = fftw_plan_r2r_1d(frame_size, m_input, m_output, FFTW_R2HC, FFTW_ESTIMATE);
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}
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FFTLib::~FFTLib()
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{
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fftw_destroy_plan(m_plan);
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fftw_free(m_input);
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fftw_free(m_output);
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}
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void FFTLib::ComputeFrame(CombinedBuffer<short>::Iterator input, double *output)
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{
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ApplyWindow(input, m_window, m_input, m_frame_size, 1.0);
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fftw_execute(m_plan);
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double *in_ptr = m_output;
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double *rev_in_ptr = m_output + m_frame_size - 1;
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output[0] = in_ptr[0] * in_ptr[0];
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output[m_frame_size / 2] = in_ptr[m_frame_size / 2] * in_ptr[m_frame_size / 2];
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in_ptr += 1;
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output += 1;
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for (int i = 1; i < m_frame_size / 2; i++) {
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*output++ = in_ptr[0] * in_ptr[0] + rev_in_ptr[0] * rev_in_ptr[0];
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in_ptr++;
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rev_in_ptr--;
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}
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}
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