fft.h 4.15 KB
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/*
 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
 *
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 * This file is part of Libav.
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 *
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 * Libav is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
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 * Libav is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
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 * License along with Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef AVCODEC_FFT_H
#define AVCODEC_FFT_H

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#ifndef CONFIG_FFT_FLOAT
#define CONFIG_FFT_FLOAT 1
#endif

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#include <stdint.h>
#include "config.h"
#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

typedef float FFTDouble;

#else

#define FFT_NAME(x) x ## _fixed

typedef int16_t FFTSample;
typedef int     FFTDouble;

typedef struct FFTComplex {
    int16_t re, im;
} FFTComplex;

typedef struct FFTContext FFTContext;

#endif /* CONFIG_FFT_FLOAT */

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typedef struct FFTDComplex {
    FFTDouble re, im;
} FFTDComplex;

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/* FFT computation */

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struct FFTContext {
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    int nbits;
    int inverse;
    uint16_t *revtab;
    FFTComplex *tmp_buf;
    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 */
    FFTSample *tcos;
    FFTSample *tsin;
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    /**
     * Do the permutation needed BEFORE calling fft_calc().
     */
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    void (*fft_permute)(struct FFTContext *s, FFTComplex *z);
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    /**
     * Do a complex FFT with the parameters defined in ff_fft_init(). The
     * input data must be permuted before. No 1.0/sqrt(n) normalization is done.
     */
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    void (*fft_calc)(struct FFTContext *s, FFTComplex *z);
    void (*imdct_calc)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
    void (*imdct_half)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
    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;
#define FF_FFT_PERM_DEFAULT   0
#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
#define FF_MDCT_PERM_INTERLEAVE 1
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};
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#if CONFIG_HARDCODED_TABLES
#define COSTABLE_CONST const
#else
#define COSTABLE_CONST
#endif

#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);
extern COSTABLE(32);
extern COSTABLE(64);
extern COSTABLE(128);
extern COSTABLE(256);
extern COSTABLE(512);
extern COSTABLE(1024);
extern COSTABLE(2048);
extern COSTABLE(4096);
extern COSTABLE(8192);
extern COSTABLE(16384);
extern COSTABLE(32768);
extern COSTABLE(65536);
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extern COSTABLE_CONST FFTSample* const FFT_NAME(ff_cos_tabs)[17];

#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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 */
void ff_init_ff_cos_tabs(int index);

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#define ff_fft_init FFT_NAME(ff_fft_init)
#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
 * @param inverse         if 0 perform the forward transform, if 1 perform the inverse
 */
int ff_fft_init(FFTContext *s, int nbits, int inverse);

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#if CONFIG_FFT_FLOAT
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void ff_fft_init_altivec(FFTContext *s);
void ff_fft_init_mmx(FFTContext *s);
void ff_fft_init_arm(FFTContext *s);
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#else
void ff_fft_fixed_init_arm(FFTContext *s);
#endif
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void ff_fft_end(FFTContext *s);

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#define ff_mdct_init FFT_NAME(ff_mdct_init)
#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);
void ff_mdct_end(FFTContext *s);

#endif /* AVCODEC_FFT_H */