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[Visualizer] Add PFFFT implementation for example 

The PFFFT implementation is actually slower than Apple's float DFT code.

Signed-off-by: Christopher Snowhill <kode54@gmail.com>
swiftingly
Christopher Snowhill 2022-06-11 02:21:17 -07:00
parent b3b4d728f9
commit 7b18a9f398
1 changed files with 101 additions and 0 deletions
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101
Audio/ThirdParty/deadbeef/fft_pffft.c vendored Normal file
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/*
DeaDBeeF -- the music player
Copyright (C) 2009-2021 Alexey Yakovenko and other contributors
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
#include "fft.h"
#include "pffft.h"
#include <Accelerate/Accelerate.h>
static int _fft_size;
static float *_input;
static float *_output;
static float *_output_real;
static float *_output_imaginary;
static float *_work;
static float *_hamming;
static float *_sq_mags;
static PFFFT_Setup *_fft_setup;
static void
_init_buffers(int fft_size) {
if(fft_size != _fft_size) {
fft_free();
_input = pffft_aligned_malloc(fft_size * 4 * sizeof(float));
_hamming = pffft_aligned_malloc(fft_size * 2 * sizeof(float));
_sq_mags = pffft_aligned_malloc(fft_size * sizeof(float));
_output = pffft_aligned_malloc(fft_size * 4 * sizeof(float));
_output_real = pffft_aligned_malloc(fft_size * 2 * sizeof(float));
_output_imaginary = pffft_aligned_malloc(fft_size * 2 * sizeof(float));
_work = pffft_aligned_malloc(fft_size * 4 * sizeof(float));
bzero(_input, fft_size * 4 * sizeof(float));
_fft_setup = pffft_new_setup(fft_size * 2, PFFFT_COMPLEX);
vDSP_hamm_window(_hamming, fft_size * 2, 0);
_fft_size = fft_size;
}
}
void fft_calculate(const float *data, float *freq, int fft_size) {
int dft_size = fft_size * 2;
_init_buffers(fft_size);
vDSP_vmul(data, 1, _hamming, 1, _input, 2, dft_size);
pffft_transform_ordered(_fft_setup, _input, _output, _work, PFFFT_FORWARD);
DSPSplitComplex split_complex = {
.realp = _output_real,
.imagp = _output_imaginary
};
vDSP_ctoz((const DSPComplex *)_output, 2, &split_complex, 1, dft_size);
vDSP_zvmags(&split_complex, 1, _sq_mags, 1, fft_size);
int sq_count = fft_size;
vvsqrtf(_sq_mags, _sq_mags, &sq_count);
float mult = 2.f / fft_size;
vDSP_vsmul(_sq_mags, 1, &mult, freq, 1, fft_size);
}
void fft_free(void) {
pffft_aligned_free(_input);
pffft_aligned_free(_hamming);
pffft_aligned_free(_sq_mags);
pffft_aligned_free(_output);
pffft_aligned_free(_output_real);
pffft_aligned_free(_output_imaginary);
if(_fft_setup != NULL) {
pffft_destroy_setup(_fft_setup);
}
_input = NULL;
_hamming = NULL;
_sq_mags = NULL;
_fft_setup = NULL;
_output = NULL;
_output_real = NULL;
_output_imaginary = NULL;
}