blob: 0b0ea40682dc87d5e29d59bfd9b7f79033d9aef9
| 1 | /* |
| 2 | * Header file for hardcoded mpegaudiodec tables |
| 3 | * |
| 4 | * Copyright (c) 2009 Reimar Döffinger <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 | #include "libavutil/attributes.h" |
| 29 | |
| 30 | #define TABLE_4_3_SIZE (8191 + 16)*4 |
| 31 | #if CONFIG_HARDCODED_TABLES |
| 32 | #define mpegaudio_tableinit() |
| 33 | #include "libavcodec/mpegaudio_tables.h" |
| 34 | #else |
| 35 | static int8_t table_4_3_exp[TABLE_4_3_SIZE]; |
| 36 | static uint32_t table_4_3_value[TABLE_4_3_SIZE]; |
| 37 | static uint32_t exp_table_fixed[512]; |
| 38 | static uint32_t expval_table_fixed[512][16]; |
| 39 | static float exp_table_float[512]; |
| 40 | static float expval_table_float[512][16]; |
| 41 | |
| 42 | #define FRAC_BITS 23 |
| 43 | #define IMDCT_SCALAR 1.759 |
| 44 | |
| 45 | static av_cold void mpegaudio_tableinit(void) |
| 46 | { |
| 47 | int i, value, exponent; |
| 48 | static const double exp2_lut[4] = { |
| 49 | 1.00000000000000000000, /* 2 ^ (0 * 0.25) */ |
| 50 | 1.18920711500272106672, /* 2 ^ (1 * 0.25) */ |
| 51 | M_SQRT2 , /* 2 ^ (2 * 0.25) */ |
| 52 | 1.68179283050742908606, /* 2 ^ (3 * 0.25) */ |
| 53 | }; |
| 54 | static double pow43_lut[16]; |
| 55 | double exp2_base = 2.11758236813575084767080625169910490512847900390625e-22; // 2^(-72) |
| 56 | double exp2_val; |
| 57 | double pow43_val = 0; |
| 58 | for (i = 0; i < 16; ++i) |
| 59 | pow43_lut[i] = i * cbrt(i); |
| 60 | |
| 61 | for (i = 1; i < TABLE_4_3_SIZE; i++) { |
| 62 | double f, fm; |
| 63 | int e, m; |
| 64 | double value = i / 4; |
| 65 | if ((i & 3) == 0) |
| 66 | pow43_val = value / IMDCT_SCALAR * cbrt(value); |
| 67 | f = pow43_val * exp2_lut[i & 3]; |
| 68 | fm = frexp(f, &e); |
| 69 | m = llrint(fm * (1LL << 31)); |
| 70 | e += FRAC_BITS - 31 + 5 - 100; |
| 71 | |
| 72 | /* normalized to FRAC_BITS */ |
| 73 | table_4_3_value[i] = m; |
| 74 | table_4_3_exp[i] = -e; |
| 75 | } |
| 76 | for (exponent = 0; exponent < 512; exponent++) { |
| 77 | if (exponent && (exponent & 3) == 0) |
| 78 | exp2_base *= 2; |
| 79 | exp2_val = exp2_base * exp2_lut[exponent & 3] / IMDCT_SCALAR; |
| 80 | for (value = 0; value < 16; value++) { |
| 81 | double f = pow43_lut[value] * exp2_val; |
| 82 | expval_table_fixed[exponent][value] = (f < 0xFFFFFFFF ? llrint(f) : 0xFFFFFFFF); |
| 83 | expval_table_float[exponent][value] = f; |
| 84 | } |
| 85 | exp_table_fixed[exponent] = expval_table_fixed[exponent][1]; |
| 86 | exp_table_float[exponent] = expval_table_float[exponent][1]; |
| 87 | } |
| 88 | } |
| 89 | #endif /* CONFIG_HARDCODED_TABLES */ |
| 90 | |
| 91 | #endif /* AVCODEC_MPEGAUDIO_TABLEGEN_H */ |
| 92 |