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Diffstat (limited to 'media/ffvpx/libavcodec/mpegaudiodec_common_tablegen.h')
| -rw-r--r-- | media/ffvpx/libavcodec/mpegaudiodec_common_tablegen.h | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/media/ffvpx/libavcodec/mpegaudiodec_common_tablegen.h b/media/ffvpx/libavcodec/mpegaudiodec_common_tablegen.h new file mode 100644 index 0000000000..bf402c9d84 --- /dev/null +++ b/media/ffvpx/libavcodec/mpegaudiodec_common_tablegen.h @@ -0,0 +1,72 @@ +/* + * 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 */ |