apps/codecs/lib/fft.h

   1 /*
   2  * WMA compatible decoder
   3  * Copyright (c) 2002 The FFmpeg Project.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19 #ifndef CODECLIB_FFT_H_INCLUDED
  20 #define CODECLIB_FFT_H_INCLUDED
  21
  22 #include <inttypes.h>
  23 typedef int32_t fixed32;
  24 typedef int64_t fixed64;
  25
  26 #define FFT_FIXED
  27
  28 #ifdef FFT_FIXED
  29 typedef fixed32 FFTSample;
  30 #else /* FFT_FIXED */
  31 typedef float   FFTSample;
  32 #endif /* FFT_FIXED */
  33
  34 typedef struct FFTComplex {
  35     FFTSample re, im;
  36 } FFTComplex;
  37
  38 typedef struct FFTContext {
  39     int nbits;
  40     int inverse;
  41     uint16_t *revtab;
  42     int mdct_size; /* size of MDCT (i.e. number of input data * 2) */
  43     int mdct_bits; /* n = 2^nbits */
  44     /* pre/post rotation tables */
  45     FFTSample *tcos;
  46     FFTSample *tsin;
  47     void (*fft_permute)(struct FFTContext *s, FFTComplex *z);
  48     void (*fft_calc)(struct FFTContext *s, FFTComplex *z);
  49     void (*imdct_calc)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
  50     void (*imdct_half)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
  51     void (*mdct_calc)(struct FFTContext *s, FFTSample *output, const FFTSample *input);
  52     int split_radix;
  53     int permutation;
  54 #define FF_MDCT_PERM_NONE       0
  55 #define FF_MDCT_PERM_INTERLEAVE 1
  56 } FFTContext;
  57
  58 // internal api  (fft<->mdct)
  59 //int fft_calc_unscaled(FFTContext *s, FFTComplex *z);
  60 //void ff_fft_permute_c(FFTContext *s, FFTComplex *z); // internal only?
  61 void ff_fft_calc_c(int nbits, FFTComplex *z);
  62
  63 #endif // CODECLIB_FFT_H_INCLUDED
  64