| /* |
| * Header file for hardcoded shared mpegaudiodec tables |
| * |
| * Copyright (c) 2009 Reimar Döffinger <Reimar.Doeffinger@gmx.de> |
| * Copyright (c) 2020 Andreas Rheinhardt <andreas.rheinhardt@gmail.com> |
| * |
| * 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_MPEGAUDIODEC_COMMON_TABLEGEN_H |
| #define AVCODEC_MPEGAUDIODEC_COMMON_TABLEGEN_H |
| |
| #include <stdint.h> |
| |
| #define TABLE_4_3_SIZE ((8191 + 16)*4) |
| |
| #if CONFIG_HARDCODED_TABLES |
| #define mpegaudiodec_common_tableinit() |
| #include "libavcodec/mpegaudiodec_common_tables.h" |
| #else |
| #include <math.h> |
| #include "libavutil/attributes.h" |
| |
| int8_t ff_table_4_3_exp [TABLE_4_3_SIZE]; |
| uint32_t ff_table_4_3_value[TABLE_4_3_SIZE]; |
| |
| #define FRAC_BITS 23 |
| #define IMDCT_SCALAR 1.759 |
| |
| static av_cold void mpegaudiodec_common_tableinit(void) |
| { |
| 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_val = 0; |
| |
| for (int i = 1; i < TABLE_4_3_SIZE; i++) { |
| double f, fm; |
| int e, m; |
| double value = i / 4; |
| if ((i & 3) == 0) |
| pow43_val = value / IMDCT_SCALAR * cbrt(value); |
| f = pow43_val * exp2_lut[i & 3]; |
| fm = frexp(f, &e); |
| m = llrint(fm * (1LL << 31)); |
| e += FRAC_BITS - 31 + 5 - 100; |
| |
| /* normalized to FRAC_BITS */ |
| ff_table_4_3_value[i] = m; |
| ff_table_4_3_exp [i] = -e; |
| } |
| } |
| |
| #endif /* CONFIG_HARDCODED_TABLES */ |
| #endif /* AVCODEC_MPEGAUDIODEC_COMMON_TABLEGEN_H */ |