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/*
* Header file for hardcoded mpegaudiodec tables
*
* Copyright (c) 2009 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVCODEC_MPEGAUDIO_TABLEGEN_H
#define AVCODEC_MPEGAUDIO_TABLEGEN_H
#include <stdint.h>
#include <math.h>
#define TABLE_4_3_SIZE (8191 + 16)*4
#if CONFIG_HARDCODED_TABLES
#define mpegaudio_tableinit()
#include "libavcodec/mpegaudio_tables.h"
#else
static int8_t table_4_3_exp[TABLE_4_3_SIZE];
static uint32_t table_4_3_value[TABLE_4_3_SIZE];
static uint32_t exp_table_fixed[512];
static uint32_t expval_table_fixed[512][16];
static float exp_table_float[512];
static float expval_table_float[512][16];
#define FRAC_BITS 23
#define IMDCT_SCALAR 1.759
static void mpegaudio_tableinit(void)
{
int i, value, exponent;
for (i = 1; i < TABLE_4_3_SIZE; i++) {
double value = i / 4;
double f, fm;
int e, m;
/* cbrtf() isn't available on all systems, so we use powf(). */
f = value / IMDCT_SCALAR * pow(value, 1.0 / 3.0) * pow(2, (i & 3) * 0.25);
fm = frexp(f, &e);
m = (uint32_t)(fm * (1LL << 31) + 0.5);
e += FRAC_BITS - 31 + 5 - 100;
/* normalized to FRAC_BITS */
table_4_3_value[i] = m;
table_4_3_exp[i] = -e;
}
for (exponent = 0; exponent < 512; exponent++) {
for (value = 0; value < 16; value++) {
/* cbrtf() isn't available on all systems, so we use powf(). */
double f = (double)value * pow(value, 1.0 / 3.0) * pow(2, (exponent - 400) * 0.25 + FRAC_BITS + 5) / IMDCT_SCALAR;
/* llrint() isn't always available, so round and cast manually. */
expval_table_fixed[exponent][value] = (long long int) floor(f + 0.5);
expval_table_float[exponent][value] = f;
}
exp_table_fixed[exponent] = expval_table_fixed[exponent][1];
exp_table_float[exponent] = expval_table_float[exponent][1];
}
}
#endif /* CONFIG_HARDCODED_TABLES */
#endif /* AVCODEC_MPEGAUDIO_TABLEGEN_H */
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