FFmpeg
mpegaudio_tablegen.h
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1 /*
2  * Header file for hardcoded mpegaudiodec tables
3  *
4  * Copyright (c) 2009 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 #ifndef AVCODEC_MPEGAUDIO_TABLEGEN_H
24 #define AVCODEC_MPEGAUDIO_TABLEGEN_H
25 
26 #include <stdint.h>
27 #include <math.h>
28 #include "libavutil/attributes.h"
29 
30 #define TABLE_4_3_SIZE (8191 + 16)*4
31 #if CONFIG_HARDCODED_TABLES
32 #define mpegaudio_tableinit()
33 #include "libavcodec/mpegaudio_tables.h"
34 #else
37 static uint32_t exp_table_fixed[512];
38 static uint32_t expval_table_fixed[512][16];
39 static float exp_table_float[512];
40 static float expval_table_float[512][16];
41 
42 #define FRAC_BITS 23
43 #define IMDCT_SCALAR 1.759
44 
45 static av_cold void mpegaudio_tableinit(void)
46 {
47  int i, value, exponent;
48  static const double exp2_lut[4] = {
49  1.00000000000000000000, /* 2 ^ (0 * 0.25) */
50  1.18920711500272106672, /* 2 ^ (1 * 0.25) */
51  M_SQRT2 , /* 2 ^ (2 * 0.25) */
52  1.68179283050742908606, /* 2 ^ (3 * 0.25) */
53  };
54  static double pow43_lut[16];
55  double exp2_base = 2.11758236813575084767080625169910490512847900390625e-22; // 2^(-72)
56  double exp2_val;
57  double pow43_val = 0;
58  for (i = 0; i < 16; ++i)
59  pow43_lut[i] = i * cbrt(i);
60 
61  for (i = 1; i < TABLE_4_3_SIZE; i++) {
62  double f, fm;
63  int e, m;
64  double value = i / 4;
65  if ((i & 3) == 0)
66  pow43_val = value / IMDCT_SCALAR * cbrt(value);
67  f = pow43_val * exp2_lut[i & 3];
68  fm = frexp(f, &e);
69  m = llrint(fm * (1LL << 31));
70  e += FRAC_BITS - 31 + 5 - 100;
71 
72  /* normalized to FRAC_BITS */
73  table_4_3_value[i] = m;
74  table_4_3_exp[i] = -e;
75  }
76  for (exponent = 0; exponent < 512; exponent++) {
77  if (exponent && (exponent & 3) == 0)
78  exp2_base *= 2;
79  exp2_val = exp2_base * exp2_lut[exponent & 3] / IMDCT_SCALAR;
80  for (value = 0; value < 16; value++) {
81  double f = pow43_lut[value] * exp2_val;
82  expval_table_fixed[exponent][value] = (f < 0xFFFFFFFF ? llrint(f) : 0xFFFFFFFF);
83  expval_table_float[exponent][value] = f;
84  }
85  exp_table_fixed[exponent] = expval_table_fixed[exponent][1];
86  exp_table_float[exponent] = expval_table_float[exponent][1];
87  }
88 }
89 #endif /* CONFIG_HARDCODED_TABLES */
90 
91 #endif /* AVCODEC_MPEGAUDIO_TABLEGEN_H */
static uint32_t table_4_3_value[TABLE_4_3_SIZE]
static int8_t table_4_3_exp[TABLE_4_3_SIZE]
Macro definitions for various function/variable attributes.
#define FRAC_BITS
#define TABLE_4_3_SIZE
#define av_cold
Definition: attributes.h:82
#define f(width, name)
Definition: cbs_vp9.c:255
static float exp_table_float[512]
GLsizei GLboolean const GLfloat * value
Definition: opengl_enc.c:108
static av_cold void mpegaudio_tableinit(void)
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
#define cbrt
Definition: tablegen.h:35
static uint32_t expval_table_fixed[512][16]
#define IMDCT_SCALAR
#define llrint(x)
Definition: libm.h:394
#define M_SQRT2
Definition: mathematics.h:61
static float expval_table_float[512][16]
static uint32_t exp_table_fixed[512]