2 Copyright (C) 2008 Paul Davis
3 Author: Sampo Savolainen
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
26 FFT::FFT(uint32_t windowSize)
27 : _window_size(windowSize),
28 _data_size(_window_size/2),
31 _fftInput = (float *) fftwf_malloc(sizeof(float) * _window_size);
33 _fftOutput = (float *) fftwf_malloc(sizeof(float) * _window_size);
35 _power_at_bin = (float *) malloc(sizeof(float) * _data_size);
36 _phase_at_bin = (float *) malloc(sizeof(float) * _data_size);
38 _plan = fftwf_plan_r2r_1d(_window_size, _fftInput, _fftOutput, FFTW_R2HC, FFTW_ESTIMATE);
46 memset(_power_at_bin, 0, sizeof(float) * _data_size);
47 memset(_phase_at_bin, 0, sizeof(float) * _data_size);
53 FFT::analyze(ARDOUR::Sample *input)
57 memcpy(_fftInput, input, sizeof(float) * _window_size);
61 _power_at_bin[0] += _fftOutput[0] * _fftOutput[0];
62 _phase_at_bin[0] += 0.0;
67 #define Re (_fftOutput[i])
68 #define Im (_fftOutput[_window_size-i])
69 for (uint32_t i=1; i < _data_size - 1; i++) {
71 power = (Re * Re) + (Im * Im);
72 phase = atanf(Im / Re);
74 if (Re < 0.0 && Im > 0.0) {
76 } else if (Re < 0.0 && Im < 0.0) {
80 _power_at_bin[i] += power;
81 _phase_at_bin[i] += phase;
90 if (_iterations > 1) {
91 for (uint32_t i=0; i < _data_size - 1; i++) {
92 _power_at_bin[i] /= (float)_iterations;
93 _phase_at_bin[i] /= (float)_iterations;
102 fftwf_destroy_plan(_plan);