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  1. /*
  2.  * This file is part of FFmpeg.
  3.  *
  4.  * FFmpeg is free software; you can redistribute it and/or
  5.  * modify it under the terms of the GNU Lesser General Public
  6.  * License as published by the Free Software Foundation; either
  7.  * version 2.1 of the License, or (at your option) any later version.
  8.  *
  9.  * FFmpeg is distributed in the hope that it will be useful,
  10.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12.  * Lesser General Public License for more details.
  13.  *
  14.  * You should have received a copy of the GNU Lesser General Public
  15.  * License along with FFmpeg; if not, write to the Free Software
  16.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  17.  */
  18.  
  19. #define CONFIG_FFT_FLOAT 0
  20. #define CONFIG_FFT_FIXED_32 0
  21. #include "mdct.c"
  22.  
  23. /* same as ff_mdct_calcw_c with double-width unscaled output */
  24. void ff_mdct_calcw_c(FFTContext *s, FFTDouble *out, const FFTSample *input)
  25. {
  26.     int i, j, n, n8, n4, n2, n3;
  27.     FFTDouble re, im;
  28.     const uint16_t *revtab = s->revtab;
  29.     const FFTSample *tcos = s->tcos;
  30.     const FFTSample *tsin = s->tsin;
  31.     FFTComplex *x = s->tmp_buf;
  32.     FFTDComplex *o = (FFTDComplex *)out;
  33.  
  34.     n = 1 << s->mdct_bits;
  35.     n2 = n >> 1;
  36.     n4 = n >> 2;
  37.     n8 = n >> 3;
  38.     n3 = 3 * n4;
  39.  
  40.     /* pre rotation */
  41.     for(i=0;i<n8;i++) {
  42.         re = RSCALE(-input[2*i+n3] - input[n3-1-2*i]);
  43.         im = RSCALE(-input[n4+2*i] + input[n4-1-2*i]);
  44.         j = revtab[i];
  45.         CMUL(x[j].re, x[j].im, re, im, -tcos[i], tsin[i]);
  46.  
  47.         re = RSCALE( input[2*i]    - input[n2-1-2*i]);
  48.         im = RSCALE(-input[n2+2*i] - input[ n-1-2*i]);
  49.         j = revtab[n8 + i];
  50.         CMUL(x[j].re, x[j].im, re, im, -tcos[n8 + i], tsin[n8 + i]);
  51.     }
  52.  
  53.     s->fft_calc(s, x);
  54.  
  55.     /* post rotation */
  56.     for(i=0;i<n8;i++) {
  57.         FFTDouble r0, i0, r1, i1;
  58.         CMULL(i1, r0, x[n8-i-1].re, x[n8-i-1].im, -tsin[n8-i-1], -tcos[n8-i-1]);
  59.         CMULL(i0, r1, x[n8+i  ].re, x[n8+i  ].im, -tsin[n8+i  ], -tcos[n8+i  ]);
  60.         o[n8-i-1].re = r0;
  61.         o[n8-i-1].im = i0;
  62.         o[n8+i  ].re = r1;
  63.         o[n8+i  ].im = i1;
  64.     }
  65. }
  66.