2 * Header file for hardcoded mpegaudiodec tables
4 * Copyright (c) 2009 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
6 * This file is part of FFmpeg.
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.
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.
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
23 #ifndef AVCODEC_MPEGAUDIO_TABLEGEN_H
24 #define AVCODEC_MPEGAUDIO_TABLEGEN_H
28 #include "libavutil/attributes.h"
30 #define TABLE_4_3_SIZE (8191 + 16)*4
31 #if CONFIG_HARDCODED_TABLES
32 #define mpegaudio_tableinit()
33 #include "libavcodec/mpegaudio_tables.h"
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];
43 #define IMDCT_SCALAR 1.759
45 static av_cold
void mpegaudio_tableinit(void)
47 int i
, value
, exponent
;
48 for (i
= 1; i
< TABLE_4_3_SIZE
; i
++) {
52 /* cbrtf() isn't available on all systems, so we use powf(). */
53 f
= value
/ IMDCT_SCALAR
* pow(value
, 1.0 / 3.0) * pow(2, (i
& 3) * 0.25);
55 m
= (uint32_t)(fm
* (1LL << 31) + 0.5);
56 e
+= FRAC_BITS
- 31 + 5 - 100;
58 /* normalized to FRAC_BITS */
59 table_4_3_value
[i
] = m
;
60 table_4_3_exp
[i
] = -e
;
62 for (exponent
= 0; exponent
< 512; exponent
++) {
63 for (value
= 0; value
< 16; value
++) {
64 /* cbrtf() isn't available on all systems, so we use powf(). */
65 double f
= (double)value
* pow(value
, 1.0 / 3.0) * pow(2, (exponent
- 400) * 0.25 + FRAC_BITS
+ 5) / IMDCT_SCALAR
;
66 /* llrint() isn't always available, so round and cast manually. */
67 expval_table_fixed
[exponent
][value
] = (long long int) (f
< 0xFFFFFFFF ? floor(f
+ 0.5) : 0xFFFFFFFF);
68 expval_table_float
[exponent
][value
] = f
;
70 exp_table_fixed
[exponent
] = expval_table_fixed
[exponent
][1];
71 exp_table_float
[exponent
] = expval_table_float
[exponent
][1];
74 #endif /* CONFIG_HARDCODED_TABLES */
76 #endif /* AVCODEC_MPEGAUDIO_TABLEGEN_H */