FFmpeg
libavcodec
mpegaudiodec_common_tablegen.h
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/*
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* Header file for hardcoded shared mpegaudiodec tables
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*
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* Copyright (c) 2009 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
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* Copyright (c) 2020 Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
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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_MPEGAUDIODEC_COMMON_TABLEGEN_H
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#define AVCODEC_MPEGAUDIODEC_COMMON_TABLEGEN_H
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#include <stdint.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 mpegaudiodec_common_tableinit()
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#include "libavcodec/mpegaudiodec_common_tables.h"
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#else
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#include <math.h>
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#include "
libavutil/attributes.h
"
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int8_t
ff_table_4_3_exp
[
TABLE_4_3_SIZE
];
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uint32_t
ff_table_4_3_value
[
TABLE_4_3_SIZE
];
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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
mpegaudiodec_common_tableinit
(
void
)
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{
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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_val = 0;
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for
(
int
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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ff_table_4_3_value
[
i
] = m;
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ff_table_4_3_exp
[
i
] = -e;
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}
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}
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#endif
/* CONFIG_HARDCODED_TABLES */
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#endif
/* AVCODEC_MPEGAUDIODEC_COMMON_TABLEGEN_H */
cbrt
#define cbrt
Definition:
tablegen.h:35
av_cold
#define av_cold
Definition:
attributes.h:90
ff_table_4_3_value
uint32_t ff_table_4_3_value[TABLE_4_3_SIZE]
Definition:
mpegaudiodec_common_tablegen.h:39
IMDCT_SCALAR
#define IMDCT_SCALAR
Definition:
mpegaudiodec_common_tablegen.h:42
f
f
Definition:
af_crystalizer.c:122
attributes.h
mpegaudiodec_common_tableinit
static av_cold void mpegaudiodec_common_tableinit(void)
Definition:
mpegaudiodec_common_tablegen.h:44
i
#define i(width, name, range_min, range_max)
Definition:
cbs_h2645.c:256
value
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf default value
Definition:
writing_filters.txt:86
TABLE_4_3_SIZE
#define TABLE_4_3_SIZE
Definition:
mpegaudiodec_common_tablegen.h:29
ff_table_4_3_exp
int8_t ff_table_4_3_exp[TABLE_4_3_SIZE]
Definition:
mpegaudiodec_common_tablegen.h:38
llrint
#define llrint(x)
Definition:
libm.h:394
M_SQRT2
#define M_SQRT2
Definition:
mathematics.h:109
FRAC_BITS
#define FRAC_BITS
Definition:
mpegaudiodec_common_tablegen.h:41
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