FFmpeg
mdct_fixed.c
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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 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 */
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 }
float FFTDouble
Definition: fft.h:43
float re
Definition: fft.c:82
#define CMUL(dre, dim, are, aim, bre, bim)
Definition: fft-internal.h:76
FFTDouble re
Definition: fft.h:72
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
#define CMULL(dre, dim, are, aim, bre, bim)
Definition: fft-internal.h:79
float FFTSample
Definition: avfft.h:35
Definition: fft.h:88
FFTSample * tsin
Definition: fft.h:97
void ff_mdct_calcw_c(FFTContext *s, FFTDouble *out, const FFTSample *input)
Definition: mdct_fixed.c:24
#define s(width, name)
Definition: cbs_vp9.c:257
int n
Definition: avisynth_c.h:760
#define RSCALE(x, y)
Definition: mdct_template.c:36
int mdct_bits
Definition: fft.h:94
float im
Definition: fft.c:82
and forward the test the status of outputs and forward it to the corresponding return FFERROR_NOT_READY If the filters stores internally one or a few frame for some input
MDCT/IMDCT transforms.
void(* fft_calc)(struct FFTContext *s, FFTComplex *z)
Do a complex FFT with the parameters defined in ff_fft_init().
Definition: fft.h:106
FFTSample * tcos
Definition: fft.h:96
FFTDouble im
Definition: fft.h:72
FILE * out
Definition: movenc.c:54
uint16_t * revtab
Definition: fft.h:91
FFTComplex * tmp_buf
Definition: fft.h:92