libavcodec/fft.h

   1 /*
   2  * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
   3  * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #ifndef AVCODEC_FFT_H
  23 #define AVCODEC_FFT_H
  24
  25 #include <stdint.h>
  26 #include "config.h"
  27 #include "libavutil/mem.h"
  28
  29 /* FFT computation */
  30
  31 /* NOTE: soon integer code will be added, so you must use the
  32    FFTSample type */
  33 typedef float FFTSample;
  34
  35 typedef struct FFTComplex {
  36     FFTSample re, im;
  37 } FFTComplex;
  38
  39 typedef struct FFTContext {
  40     int nbits;
  41     int inverse;
  42     uint16_t *revtab;
  43     FFTComplex *exptab;
  44     FFTComplex *exptab1; /* only used by SSE code */
  45     FFTComplex *tmp_buf;
  46     int mdct_size; /* size of MDCT (i.e. number of input data * 2) */
  47     int mdct_bits; /* n = 2^nbits */
  48     /* pre/post rotation tables */
  49     FFTSample *tcos;
  50     FFTSample *tsin;
  51     void (*fft_permute)(struct FFTContext *s, FFTComplex *z);
  52     void (*fft_calc)(struct FFTContext *s, FFTComplex *z);
  53     void (*imdct_calc)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
  54     void (*imdct_half)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
  55     void (*mdct_calc)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
  56     int split_radix;
  57     int permutation;
  58 #define FF_MDCT_PERM_NONE       0
  59 #define FF_MDCT_PERM_INTERLEAVE 1
  60 } FFTContext;
  61
  62 #if CONFIG_HARDCODED_TABLES
  63 #define COSTABLE_CONST const
  64 #define SINTABLE_CONST const
  65 #define SINETABLE_CONST const
  66 #else
  67 #define COSTABLE_CONST
  68 #define SINTABLE_CONST
  69 #define SINETABLE_CONST
  70 #endif
  71
  72 #define COSTABLE(size) \
  73     COSTABLE_CONST DECLARE_ALIGNED(16, FFTSample, ff_cos_##size)[size/2]
  74 #define SINTABLE(size) \
  75     SINTABLE_CONST DECLARE_ALIGNED(16, FFTSample, ff_sin_##size)[size/2]
  76 #define SINETABLE(size) \
  77     SINETABLE_CONST DECLARE_ALIGNED(16, float, ff_sine_##size)[size]
  78 extern COSTABLE(16);
  79 extern COSTABLE(32);
  80 extern COSTABLE(64);
  81 extern COSTABLE(128);
  82 extern COSTABLE(256);
  83 extern COSTABLE(512);
  84 extern COSTABLE(1024);
  85 extern COSTABLE(2048);
  86 extern COSTABLE(4096);
  87 extern COSTABLE(8192);
  88 extern COSTABLE(16384);
  89 extern COSTABLE(32768);
  90 extern COSTABLE(65536);
  91 extern COSTABLE_CONST FFTSample* const ff_cos_tabs[17];
  92
  93 /**
  94  * Initializes the cosine table in ff_cos_tabs[index]
  95  * \param index index in ff_cos_tabs array of the table to initialize
  96  */
  97 void ff_init_ff_cos_tabs(int index);
  98
  99 extern SINTABLE(16);
 100 extern SINTABLE(32);
 101 extern SINTABLE(64);
 102 extern SINTABLE(128);
 103 extern SINTABLE(256);
 104 extern SINTABLE(512);
 105 extern SINTABLE(1024);
 106 extern SINTABLE(2048);
 107 extern SINTABLE(4096);
 108 extern SINTABLE(8192);
 109 extern SINTABLE(16384);
 110 extern SINTABLE(32768);
 111 extern SINTABLE(65536);
 112
 113 /**
 114  * Sets up a complex FFT.
 115  * @param nbits           log2 of the length of the input array
 116  * @param inverse         if 0 perform the forward transform, if 1 perform the inverse
 117  */
 118 int ff_fft_init(FFTContext *s, int nbits, int inverse);
 119 void ff_fft_permute_c(FFTContext *s, FFTComplex *z);
 120 void ff_fft_calc_c(FFTContext *s, FFTComplex *z);
 121
 122 void ff_fft_init_altivec(FFTContext *s);
 123 void ff_fft_init_mmx(FFTContext *s);
 124 void ff_fft_init_arm(FFTContext *s);
 125
 126 /**
 127  * Do the permutation needed BEFORE calling ff_fft_calc().
 128  */
 129 static inline void ff_fft_permute(FFTContext *s, FFTComplex *z)
 130 {
 131     s->fft_permute(s, z);
 132 }
 133 /**
 134  * Do a complex FFT with the parameters defined in ff_fft_init(). The
 135  * input data must be permuted before. No 1.0/sqrt(n) normalization is done.
 136  */
 137 static inline void ff_fft_calc(FFTContext *s, FFTComplex *z)
 138 {
 139     s->fft_calc(s, z);
 140 }
 141 void ff_fft_end(FFTContext *s);
 142
 143 /* MDCT computation */
 144
 145 static inline void ff_imdct_calc(FFTContext *s, FFTSample *output, const FFTSample *input)
 146 {
 147     s->imdct_calc(s, output, input);
 148 }
 149 static inline void ff_imdct_half(FFTContext *s, FFTSample *output, const FFTSample *input)
 150 {
 151     s->imdct_half(s, output, input);
 152 }
 153
 154 static inline void ff_mdct_calc(FFTContext *s, FFTSample *output,
 155                                 const FFTSample *input)
 156 {
 157     s->mdct_calc(s, output, input);
 158 }
 159
 160 /**
 161  * Generate a Kaiser-Bessel Derived Window.
 162  * @param   window  pointer to half window
 163  * @param   alpha   determines window shape
 164  * @param   n       size of half window
 165  */
 166 void ff_kbd_window_init(float *window, float alpha, int n);
 167
 168 /**
 169  * Generate a sine window.
 170  * @param   window  pointer to half window
 171  * @param   n       size of half window
 172  */
 173 void ff_sine_window_init(float *window, int n);
 174
 175 /**
 176  * initialize the specified entry of ff_sine_windows
 177  */
 178 void ff_init_ff_sine_windows(int index);
 179 extern SINETABLE(  32);
 180 extern SINETABLE(  64);
 181 extern SINETABLE( 128);
 182 extern SINETABLE( 256);
 183 extern SINETABLE( 512);
 184 extern SINETABLE(1024);
 185 extern SINETABLE(2048);
 186 extern SINETABLE(4096);
 187 extern SINETABLE_CONST float * const ff_sine_windows[13];
 188
 189 int ff_mdct_init(FFTContext *s, int nbits, int inverse, double scale);
 190 void ff_imdct_calc_c(FFTContext *s, FFTSample *output, const FFTSample *input);
 191 void ff_imdct_half_c(FFTContext *s, FFTSample *output, const FFTSample *input);
 192 void ff_mdct_calc_c(FFTContext *s, FFTSample *output, const FFTSample *input);
 193 void ff_mdct_end(FFTContext *s);
 194
 195 /* Real Discrete Fourier Transform */
 196
 197 enum RDFTransformType {
 198     DFT_R2C,
 199     IDFT_C2R,
 200     IDFT_R2C,
 201     DFT_C2R,
 202 };
 203
 204 typedef struct {
 205     int nbits;
 206     int inverse;
 207     int sign_convention;
 208
 209     /* pre/post rotation tables */
 210     const FFTSample *tcos;
 211     SINTABLE_CONST FFTSample *tsin;
 212     FFTContext fft;
 213 } RDFTContext;
 214
 215 /**
 216  * Sets up a real FFT.
 217  * @param nbits           log2 of the length of the input array
 218  * @param trans           the type of transform
 219  */
 220 int ff_rdft_init(RDFTContext *s, int nbits, enum RDFTransformType trans);
 221 void ff_rdft_calc(RDFTContext *s, FFTSample *data);
 222 void ff_rdft_end(RDFTContext *s);
 223
 224 /* Discrete Cosine Transform */
 225
 226 typedef struct {
 227     int nbits;
 228     int inverse;
 229     FFTSample *data;
 230     RDFTContext rdft;
 231     const float *costab;
 232     FFTSample *csc2;
 233 } DCTContext;
 234
 235 /**
 236  * Sets up (Inverse)DCT.
 237  * @param nbits           log2 of the length of the input array
 238  * @param inverse         >0 forward transform, <0 inverse transform
 239  */
 240 int  ff_dct_init(DCTContext *s, int nbits, int inverse);
 241 void ff_dct_calc(DCTContext *s, FFTSample *data);
 242 void ff_dct_end (DCTContext *s);
 243
 244 #endif /* AVCODEC_FFT_H */