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18d7074b4e
Iterative implementation of 32 bit fixed point split-radix FFT. Max FFT that can be calculated currently is 2^12. Signed-off-by: Nedeljko Babic <nbabic@mips.com> Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
167 lines
4.4 KiB
C
167 lines
4.4 KiB
C
/*
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* Copyright (c) 2000, 2001, 2002 Fabrice Bellard
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* Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg 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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* FFmpeg 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 FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef AVCODEC_FFT_H
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#define AVCODEC_FFT_H
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#ifndef CONFIG_FFT_FLOAT
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#define CONFIG_FFT_FLOAT 1
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#endif
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#ifndef CONFIG_FFT_FIXED_32
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#define CONFIG_FFT_FIXED_32 0
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#endif
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#include <stdint.h>
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#include "config.h"
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#include "libavutil/mem.h"
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#if CONFIG_FFT_FLOAT
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#include "avfft.h"
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#define FFT_NAME(x) x
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typedef float FFTDouble;
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#else
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#if CONFIG_FFT_FIXED_32
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#define Q31(x) (int)((x)*2147483648.0 + 0.5)
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#define FFT_NAME(x) x ## _fixed_32
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typedef int32_t FFTSample;
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#else /* CONFIG_FFT_FIXED_32 */
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#define FFT_NAME(x) x ## _fixed
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typedef int16_t FFTSample;
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#endif /* CONFIG_FFT_FIXED_32 */
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typedef struct FFTComplex {
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FFTSample re, im;
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} FFTComplex;
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typedef int FFTDouble;
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typedef struct FFTContext FFTContext;
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#endif /* CONFIG_FFT_FLOAT */
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typedef struct FFTDComplex {
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FFTDouble re, im;
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} FFTDComplex;
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/* FFT computation */
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struct FFTContext {
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int nbits;
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int inverse;
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uint16_t *revtab;
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FFTComplex *tmp_buf;
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int mdct_size; /* size of MDCT (i.e. number of input data * 2) */
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int mdct_bits; /* n = 2^nbits */
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/* pre/post rotation tables */
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FFTSample *tcos;
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FFTSample *tsin;
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/**
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* Do the permutation needed BEFORE calling fft_calc().
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*/
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void (*fft_permute)(struct FFTContext *s, FFTComplex *z);
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/**
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* Do a complex FFT with the parameters defined in ff_fft_init(). The
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* input data must be permuted before. No 1.0/sqrt(n) normalization is done.
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*/
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void (*fft_calc)(struct FFTContext *s, FFTComplex *z);
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void (*imdct_calc)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
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void (*imdct_half)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
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void (*mdct_calc)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
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void (*mdct_calcw)(struct FFTContext *s, FFTDouble *output, const FFTSample *input);
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int fft_permutation;
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#define FF_FFT_PERM_DEFAULT 0
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#define FF_FFT_PERM_SWAP_LSBS 1
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#define FF_FFT_PERM_AVX 2
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int mdct_permutation;
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#define FF_MDCT_PERM_NONE 0
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#define FF_MDCT_PERM_INTERLEAVE 1
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};
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#if CONFIG_HARDCODED_TABLES
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#define COSTABLE_CONST const
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#else
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#define COSTABLE_CONST
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#endif
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#define COSTABLE(size) \
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COSTABLE_CONST DECLARE_ALIGNED(32, FFTSample, FFT_NAME(ff_cos_##size))[size/2]
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extern COSTABLE(16);
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extern COSTABLE(32);
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extern COSTABLE(64);
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extern COSTABLE(128);
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extern COSTABLE(256);
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extern COSTABLE(512);
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extern COSTABLE(1024);
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extern COSTABLE(2048);
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extern COSTABLE(4096);
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extern COSTABLE(8192);
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extern COSTABLE(16384);
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extern COSTABLE(32768);
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extern COSTABLE(65536);
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extern COSTABLE_CONST FFTSample* const FFT_NAME(ff_cos_tabs)[17];
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#define ff_init_ff_cos_tabs FFT_NAME(ff_init_ff_cos_tabs)
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/**
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* Initialize the cosine table in ff_cos_tabs[index]
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* @param index index in ff_cos_tabs array of the table to initialize
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*/
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void ff_init_ff_cos_tabs(int index);
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#define ff_fft_init FFT_NAME(ff_fft_init)
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#define ff_fft_end FFT_NAME(ff_fft_end)
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/**
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* Set up a complex FFT.
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* @param nbits log2 of the length of the input array
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* @param inverse if 0 perform the forward transform, if 1 perform the inverse
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*/
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int ff_fft_init(FFTContext *s, int nbits, int inverse);
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void ff_fft_init_x86(FFTContext *s);
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void ff_fft_init_arm(FFTContext *s);
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void ff_fft_init_mips(FFTContext *s);
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void ff_fft_init_ppc(FFTContext *s);
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void ff_fft_fixed_init_arm(FFTContext *s);
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void ff_fft_end(FFTContext *s);
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#define ff_mdct_init FFT_NAME(ff_mdct_init)
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#define ff_mdct_end FFT_NAME(ff_mdct_end)
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int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale);
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void ff_mdct_end(FFTContext *s);
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#endif /* AVCODEC_FFT_H */
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