1/*
2 * Header file for hardcoded mpegaudiodec tables
3 *
4 * Copyright (c) 2009 Reimar D��ffinger <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
29#define TABLE_4_3_SIZE (8191 + 16)*4
30#if CONFIG_HARDCODED_TABLES
31#define mpegaudio_tableinit()
32#include "libavcodec/mpegaudio_tables.h"
33#else
34static int8_t   table_4_3_exp[TABLE_4_3_SIZE];
35static uint32_t table_4_3_value[TABLE_4_3_SIZE];
36static uint32_t exp_table_fixed[512];
37static uint32_t expval_table_fixed[512][16];
38static float exp_table_float[512];
39static float expval_table_float[512][16];
40
41#define FRAC_BITS 23
42#define IMDCT_SCALAR 1.759
43
44static void mpegaudio_tableinit(void)
45{
46    int i, value, exponent;
47    for (i = 1; i < TABLE_4_3_SIZE; i++) {
48        double value = i / 4;
49        double f, fm;
50        int e, m;
51        /* cbrtf() isn't available on all systems, so we use powf(). */
52        f  = value / IMDCT_SCALAR * pow(value, 1.0 / 3.0) * pow(2, (i & 3) * 0.25);
53        fm = frexp(f, &e);
54        m  = (uint32_t)(fm * (1LL << 31) + 0.5);
55        e += FRAC_BITS - 31 + 5 - 100;
56
57        /* normalized to FRAC_BITS */
58        table_4_3_value[i] =  m;
59        table_4_3_exp[i]   = -e;
60    }
61    for (exponent = 0; exponent < 512; exponent++) {
62        for (value = 0; value < 16; value++) {
63            /* cbrtf() isn't available on all systems, so we use powf(). */
64            double f = (double)value * pow(value, 1.0 / 3.0) * pow(2, (exponent - 400) * 0.25 + FRAC_BITS + 5) / IMDCT_SCALAR;
65            /* llrint() isn't always available, so round and cast manually. */
66            expval_table_fixed[exponent][value] = (long long int) (f < 0xFFFFFFFF ? floor(f + 0.5) : 0xFFFFFFFF);
67            expval_table_float[exponent][value] = f;
68        }
69        exp_table_fixed[exponent] = expval_table_fixed[exponent][1];
70        exp_table_float[exponent] = expval_table_float[exponent][1];
71    }
72}
73#endif /* CONFIG_HARDCODED_TABLES */
74
75#endif /* AVCODEC_MPEGAUDIO_TABLEGEN_H */
76