FFmpeg
mpegaudiodec_common_tablegen.h
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1 /*
2  * Header file for hardcoded shared mpegaudiodec tables
3  *
4  * Copyright (c) 2009 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
5  * Copyright (c) 2020 Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
6  *
7  * This file is part of FFmpeg.
8  *
9  * FFmpeg is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU Lesser General Public
11  * License as published by the Free Software Foundation; either
12  * version 2.1 of the License, or (at your option) any later version.
13  *
14  * FFmpeg is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17  * Lesser General Public License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with FFmpeg; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22  */
23 
24 #ifndef AVCODEC_MPEGAUDIODEC_COMMON_TABLEGEN_H
25 #define AVCODEC_MPEGAUDIODEC_COMMON_TABLEGEN_H
26 
27 #include <stdint.h>
28 
29 #define TABLE_4_3_SIZE ((8191 + 16)*4)
30 
31 #if CONFIG_HARDCODED_TABLES
32 #define mpegaudiodec_common_tableinit()
33 #include "libavcodec/mpegaudiodec_common_tables.h"
34 #else
35 #include <math.h>
36 #include "libavutil/attributes.h"
37 
40 
41 #define FRAC_BITS 23
42 #define IMDCT_SCALAR 1.759
43 
45 {
46  static const double exp2_lut[4] = {
47  1.00000000000000000000, /* 2 ^ (0 * 0.25) */
48  1.18920711500272106672, /* 2 ^ (1 * 0.25) */
49  M_SQRT2 , /* 2 ^ (2 * 0.25) */
50  1.68179283050742908606, /* 2 ^ (3 * 0.25) */
51  };
52  double pow43_val = 0;
53 
54  for (int i = 1; i < TABLE_4_3_SIZE; i++) {
55  double f, fm;
56  int e, m;
57  double value = i / 4;
58  if ((i & 3) == 0)
59  pow43_val = value / IMDCT_SCALAR * cbrt(value);
60  f = pow43_val * exp2_lut[i & 3];
61  fm = frexp(f, &e);
62  m = llrint(fm * (1LL << 31));
63  e += FRAC_BITS - 31 + 5 - 100;
64 
65  /* normalized to FRAC_BITS */
66  ff_table_4_3_value[i] = m;
67  ff_table_4_3_exp [i] = -e;
68  }
69 }
70 
71 #endif /* CONFIG_HARDCODED_TABLES */
72 #endif /* AVCODEC_MPEGAUDIODEC_COMMON_TABLEGEN_H */
static av_cold void mpegaudiodec_common_tableinit(void)
Macro definitions for various function/variable attributes.
#define av_cold
Definition: attributes.h:88
#define f(width, name)
Definition: cbs_vp9.c:255
GLsizei GLboolean const GLfloat * value
Definition: opengl_enc.c:108
uint32_t ff_table_4_3_value[TABLE_4_3_SIZE]
#define IMDCT_SCALAR
#define cbrt
Definition: tablegen.h:35
int8_t ff_table_4_3_exp[TABLE_4_3_SIZE]
#define TABLE_4_3_SIZE
#define llrint(x)
Definition: libm.h:394
#define FRAC_BITS
#define M_SQRT2
Definition: mathematics.h:61
int i
Definition: input.c:407