12e941df89
Each invocation of this function is only entered once, so using a static array makes no sense (and given that the whole array is reinitialized at the beginning of this function, it wouldn't even make sense if the function were called multiple times). Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
109 lines
3.4 KiB
C
109 lines
3.4 KiB
C
/*
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* Header file for hardcoded mpegaudiodec tables
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*
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* Copyright (c) 2009 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef AVCODEC_MPEGAUDIO_TABLEGEN_H
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#define AVCODEC_MPEGAUDIO_TABLEGEN_H
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#include <stdint.h>
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#include <math.h>
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#include "libavutil/attributes.h"
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#define TABLE_4_3_SIZE (8191 + 16)*4
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#if CONFIG_HARDCODED_TABLES
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#define mpegaudio_tableinit()
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#include "libavcodec/mpegaudio_tables.h"
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#else
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static int8_t table_4_3_exp[TABLE_4_3_SIZE];
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static uint32_t table_4_3_value[TABLE_4_3_SIZE];
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#if defined(BUILD_TABLES) || !USE_FLOATS
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#define FIXED_TABLE
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static uint32_t exp_table_fixed[512];
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static uint32_t expval_table_fixed[512][16];
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#endif
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#if defined(BUILD_TABLES) || USE_FLOATS
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#define FLOAT_TABLE
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static float exp_table_float[512];
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static float expval_table_float[512][16];
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#endif
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#define FRAC_BITS 23
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#define IMDCT_SCALAR 1.759
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static av_cold void mpegaudio_tableinit(void)
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{
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int i, value, exponent;
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static const double exp2_lut[4] = {
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1.00000000000000000000, /* 2 ^ (0 * 0.25) */
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1.18920711500272106672, /* 2 ^ (1 * 0.25) */
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M_SQRT2 , /* 2 ^ (2 * 0.25) */
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1.68179283050742908606, /* 2 ^ (3 * 0.25) */
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};
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double pow43_lut[16];
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double exp2_base = 2.11758236813575084767080625169910490512847900390625e-22; // 2^(-72)
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double exp2_val;
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double pow43_val = 0;
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for (i = 0; i < 16; ++i)
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pow43_lut[i] = i * cbrt(i);
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for (i = 1; i < TABLE_4_3_SIZE; i++) {
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double f, fm;
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int e, m;
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double value = i / 4;
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if ((i & 3) == 0)
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pow43_val = value / IMDCT_SCALAR * cbrt(value);
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f = pow43_val * exp2_lut[i & 3];
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fm = frexp(f, &e);
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m = llrint(fm * (1LL << 31));
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e += FRAC_BITS - 31 + 5 - 100;
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/* normalized to FRAC_BITS */
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table_4_3_value[i] = m;
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table_4_3_exp[i] = -e;
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}
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for (exponent = 0; exponent < 512; exponent++) {
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if (exponent && (exponent & 3) == 0)
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exp2_base *= 2;
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exp2_val = exp2_base * exp2_lut[exponent & 3] / IMDCT_SCALAR;
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for (value = 0; value < 16; value++) {
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double f = pow43_lut[value] * exp2_val;
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#ifdef FIXED_TABLE
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expval_table_fixed[exponent][value] = (f < 0xFFFFFFFF ? llrint(f) : 0xFFFFFFFF);
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#endif
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#ifdef FLOAT_TABLE
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expval_table_float[exponent][value] = f;
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#endif
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}
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#ifdef FIXED_TABLE
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exp_table_fixed[exponent] = expval_table_fixed[exponent][1];
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#endif
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#ifdef FLOAT_TABLE
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exp_table_float[exponent] = expval_table_float[exponent][1];
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#endif
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}
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}
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#undef FLOAT_TABLE
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#undef FIXED_TABLE
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#endif /* CONFIG_HARDCODED_TABLES */
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#endif /* AVCODEC_MPEGAUDIO_TABLEGEN_H */
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