/* * Header file for hardcoded shared mpegaudiodec tables * * Copyright (c) 2009 Reimar Döffinger * Copyright (c) 2020 Andreas Rheinhardt * * 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 #define TABLE_4_3_SIZE ((8191 + 16)*4) #if CONFIG_HARDCODED_TABLES #define mpegaudiodec_common_tableinit() #include "libavcodec/mpegaudiodec_common_tables.h" #else #include #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 */