mirror of https://github.com/FFmpeg/FFmpeg.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
89 lines
2.8 KiB
89 lines
2.8 KiB
/* |
|
* 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> |
|
#include "libavutil/attributes.h" |
|
|
|
#if CONFIG_HARDCODED_TABLES |
|
#define mpegaudio_tableinit() |
|
#include "libavcodec/mpegaudio_tables.h" |
|
#else |
|
#if defined(BUILD_TABLES) || !USE_FLOATS |
|
#define FIXED_TABLE |
|
static uint32_t exp_table_fixed[512]; |
|
static uint32_t expval_table_fixed[512][16]; |
|
#endif |
|
|
|
#if defined(BUILD_TABLES) || USE_FLOATS |
|
#define FLOAT_TABLE |
|
static float exp_table_float[512]; |
|
static float expval_table_float[512][16]; |
|
#endif |
|
|
|
#define IMDCT_SCALAR 1.759 |
|
|
|
static av_cold void mpegaudio_tableinit(void) |
|
{ |
|
int i, value, exponent; |
|
static const double exp2_lut[4] = { |
|
1.00000000000000000000, /* 2 ^ (0 * 0.25) */ |
|
1.18920711500272106672, /* 2 ^ (1 * 0.25) */ |
|
M_SQRT2 , /* 2 ^ (2 * 0.25) */ |
|
1.68179283050742908606, /* 2 ^ (3 * 0.25) */ |
|
}; |
|
double pow43_lut[16]; |
|
double exp2_base = 2.11758236813575084767080625169910490512847900390625e-22; // 2^(-72) |
|
double exp2_val; |
|
|
|
for (i = 0; i < 16; ++i) |
|
pow43_lut[i] = i * cbrt(i); |
|
|
|
for (exponent = 0; exponent < 512; exponent++) { |
|
if (exponent && (exponent & 3) == 0) |
|
exp2_base *= 2; |
|
exp2_val = exp2_base * exp2_lut[exponent & 3] / IMDCT_SCALAR; |
|
for (value = 0; value < 16; value++) { |
|
double f = pow43_lut[value] * exp2_val; |
|
#ifdef FIXED_TABLE |
|
expval_table_fixed[exponent][value] = (f < 0xFFFFFFFF ? llrint(f) : 0xFFFFFFFF); |
|
#endif |
|
#ifdef FLOAT_TABLE |
|
expval_table_float[exponent][value] = f; |
|
#endif |
|
} |
|
#ifdef FIXED_TABLE |
|
exp_table_fixed[exponent] = expval_table_fixed[exponent][1]; |
|
#endif |
|
#ifdef FLOAT_TABLE |
|
exp_table_float[exponent] = expval_table_float[exponent][1]; |
|
#endif |
|
} |
|
} |
|
#undef FLOAT_TABLE |
|
#undef FIXED_TABLE |
|
#endif /* CONFIG_HARDCODED_TABLES */ |
|
|
|
#endif /* AVCODEC_MPEGAUDIO_TABLEGEN_H */
|
|
|