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FFmpeg/libavcodec/fft.h
Vitor Sessak e1484ebed6 Implement the discrete sine/cosine transforms DCT-I and DST-I 
Originally committed as revision 22649 to svn://svn.ffmpeg.org/ffmpeg/trunk
2010-03-23 19:48:16 +00:00

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/*
* Copyright (c) 2000, 2001, 2002 Fabrice Bellard
* Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* 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.
*
* FFmpeg is distributed in the hope that it will be useful,
* 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
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVCODEC_FFT_H
#define AVCODEC_FFT_H
#include <stdint.h>
#include "config.h"
#include "libavutil/mem.h"
#include "avfft.h"
/* FFT computation */
struct FFTContext {
int nbits;
int inverse;
uint16_t *revtab;
FFTComplex *exptab;
FFTComplex *exptab1; /* only used by SSE code */
FFTComplex *tmp_buf;
int mdct_size; /* size of MDCT (i.e. number of input data * 2) */
int mdct_bits; /* n = 2^nbits */
/* pre/post rotation tables */
FFTSample *tcos;
FFTSample *tsin;
void (*fft_permute)(struct FFTContext *s, FFTComplex *z);
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);
int split_radix;
int permutation;
#define FF_MDCT_PERM_NONE 0
#define FF_MDCT_PERM_INTERLEAVE 1
};
#if CONFIG_HARDCODED_TABLES
#define COSTABLE_CONST const
#define SINTABLE_CONST const
#define SINETABLE_CONST const
#else
#define COSTABLE_CONST
#define SINTABLE_CONST
#define SINETABLE_CONST
#endif
#define COSTABLE(size) \
COSTABLE_CONST DECLARE_ALIGNED(16, FFTSample, ff_cos_##size)[size/2]
#define SINTABLE(size) \
SINTABLE_CONST DECLARE_ALIGNED(16, FFTSample, ff_sin_##size)[size/2]
#define SINETABLE(size) \
SINETABLE_CONST DECLARE_ALIGNED(16, float, ff_sine_##size)[size]
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);
extern COSTABLE_CONST FFTSample* const ff_cos_tabs[17];
/**
* Initializes the cosine table in ff_cos_tabs[index]
* \param index index in ff_cos_tabs array of the table to initialize
*/
void ff_init_ff_cos_tabs(int index);
extern SINTABLE(16);
extern SINTABLE(32);
extern SINTABLE(64);
extern SINTABLE(128);
extern SINTABLE(256);
extern SINTABLE(512);
extern SINTABLE(1024);
extern SINTABLE(2048);
extern SINTABLE(4096);
extern SINTABLE(8192);
extern SINTABLE(16384);
extern SINTABLE(32768);
extern SINTABLE(65536);
/**
* Sets up a complex FFT.
* @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);
void ff_fft_permute_c(FFTContext *s, FFTComplex *z);
void ff_fft_calc_c(FFTContext *s, FFTComplex *z);
void ff_fft_init_altivec(FFTContext *s);
void ff_fft_init_mmx(FFTContext *s);
void ff_fft_init_arm(FFTContext *s);
/**
* Do the permutation needed BEFORE calling ff_fft_calc().
*/
static inline void ff_fft_permute(FFTContext *s, FFTComplex *z)
{
s->fft_permute(s, z);
}
/**
* 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.
*/
static inline void ff_fft_calc(FFTContext *s, FFTComplex *z)
{
s->fft_calc(s, z);
}
void ff_fft_end(FFTContext *s);
/* MDCT computation */
static inline void ff_imdct_calc(FFTContext *s, FFTSample *output, const FFTSample *input)
{
s->imdct_calc(s, output, input);
}
static inline void ff_imdct_half(FFTContext *s, FFTSample *output, const FFTSample *input)
{
s->imdct_half(s, output, input);
}
static inline void ff_mdct_calc(FFTContext *s, FFTSample *output,
const FFTSample *input)
{
s->mdct_calc(s, output, input);
}
/**
* Generate a Kaiser-Bessel Derived Window.
* @param window pointer to half window
* @param alpha determines window shape
* @param n size of half window
*/
void ff_kbd_window_init(float *window, float alpha, int n);
/**
* Generate a sine window.
* @param window pointer to half window
* @param n size of half window
*/
void ff_sine_window_init(float *window, int n);
/**
* initialize the specified entry of ff_sine_windows
*/
void ff_init_ff_sine_windows(int index);
extern SINETABLE( 32);
extern SINETABLE( 64);
extern SINETABLE( 128);
extern SINETABLE( 256);
extern SINETABLE( 512);
extern SINETABLE(1024);
extern SINETABLE(2048);
extern SINETABLE(4096);
extern SINETABLE_CONST float * const ff_sine_windows[13];
int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale);
void ff_imdct_calc_c(FFTContext *s, FFTSample *output, const FFTSample *input);
void ff_imdct_half_c(FFTContext *s, FFTSample *output, const FFTSample *input);
void ff_mdct_calc_c(FFTContext *s, FFTSample *output, const FFTSample *input);
void ff_mdct_end(FFTContext *s);
/* Real Discrete Fourier Transform */
struct RDFTContext {
int nbits;
int inverse;
int sign_convention;
/* pre/post rotation tables */
const FFTSample *tcos;
SINTABLE_CONST FFTSample *tsin;
FFTContext fft;
void (*rdft_calc)(struct RDFTContext *s, FFTSample *z);
};
/**
* Sets up a real FFT.
* @param nbits log2 of the length of the input array
* @param trans the type of transform
*/
int ff_rdft_init(RDFTContext *s, int nbits, enum RDFTransformType trans);
void ff_rdft_end(RDFTContext *s);
void ff_rdft_init_arm(RDFTContext *s);
static av_always_inline void ff_rdft_calc(RDFTContext *s, FFTSample *data)
{
s->rdft_calc(s, data);
}
/* Discrete Cosine Transform */
struct DCTContext {
int nbits;
int inverse;
RDFTContext rdft;
const float *costab;
FFTSample *csc2;
void (*dct_calc)(struct DCTContext *s, FFTSample *data);
};
/**
* Sets up DCT.
* @param nbits size of the input array:
* (1 << nbits) for DCT-II, DCT-III and DST-I
* (1 << nbits) + 1 for DCT-I
*
* @note the first element of the input of DST-I is ignored
*/
int ff_dct_init(DCTContext *s, int nbits, enum DCTTransformType type);
void ff_dct_calc(DCTContext *s, FFTSample *data);
void ff_dct_end (DCTContext *s);
#endif /* AVCODEC_FFT_H */
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