96 lines
2.7 KiB
C
96 lines
2.7 KiB
C
/*
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DeaDBeeF -- the music player
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Copyright (C) 2009-2021 Alexey Yakovenko and other contributors
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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#include "fft.h"
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#include <Accelerate/Accelerate.h>
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static int _fft_size;
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static float *_input_real;
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static float *_input_imaginary;
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static float *_output_real;
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static float *_output_imaginary;
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static float *_hamming;
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static float *_sq_mags;
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static vDSP_DFT_Setup _dft_setup;
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static void
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_init_buffers(int fft_size) {
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if(fft_size != _fft_size) {
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fft_free();
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_input_real = calloc(fft_size * 2, sizeof(float));
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_input_imaginary = calloc(fft_size * 2, sizeof(float));
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_hamming = calloc(fft_size * 2, sizeof(float));
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_sq_mags = calloc(fft_size, sizeof(float));
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_output_real = calloc(fft_size * 2, sizeof(float));
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_output_imaginary = calloc(fft_size * 2, sizeof(float));
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_dft_setup = vDSP_DFT_zop_CreateSetup(NULL, fft_size * 2, FFT_FORWARD);
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vDSP_hamm_window(_hamming, fft_size * 2, 0);
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_fft_size = fft_size;
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}
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}
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void fft_calculate(const float *data, float *freq, int fft_size) {
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int dft_size = fft_size * 2;
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_init_buffers(fft_size);
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vDSP_vmul(data, 1, _hamming, 1, _input_real, 1, dft_size);
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vDSP_DFT_Execute(_dft_setup, _input_real, _input_imaginary, _output_real, _output_imaginary);
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DSPSplitComplex split_complex = {
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.realp = _output_real,
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.imagp = _output_imaginary
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};
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vDSP_zvmags(&split_complex, 1, _sq_mags, 1, fft_size);
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int sq_count = fft_size;
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vvsqrtf(_sq_mags, _sq_mags, &sq_count);
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float mult = 2.f / fft_size;
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vDSP_vsmul(_sq_mags, 1, &mult, freq, 1, fft_size);
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}
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void fft_free(void) {
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free(_input_real);
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free(_input_imaginary);
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free(_hamming);
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free(_sq_mags);
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free(_output_real);
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free(_output_imaginary);
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if(_dft_setup != NULL) {
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vDSP_DFT_DestroySetup(_dft_setup);
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}
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_input_real = NULL;
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_input_imaginary = NULL;
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_hamming = NULL;
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_sq_mags = NULL;
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_dft_setup = NULL;
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_output_real = NULL;
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_output_imaginary = NULL;
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}
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