0,0 → 1,75 |
/* |
* 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) (f < 0xFFFFFFFF ? floor(f + 0.5) : 0xFFFFFFFF); |
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 */ |