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 FFT_FLOAT 0
20 #define FFT_FIXED_32 0
21 #include "mdct_template.c"
22
23 /* same as ff_mdct_calcw_c with double-width unscaled output */
ff_mdct_calcw_c(FFTContext * s,FFTDouble * out,const FFTSample * input)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