FFmpeg: libavcodec/mpegaudiotab.h Source File

00001 /*
00002  * mpeg audio layer 2 tables. Most of them come from the mpeg audio
00003  * specification.
00004  *
00005  * Copyright (c) 2000, 2001 Fabrice Bellard
00006  *
00007  * This file is part of FFmpeg.
00008  *
00009  * FFmpeg is free software; you can redistribute it and/or
00010  * modify it under the terms of the GNU Lesser General Public
00011  * License as published by the Free Software Foundation; either
00012  * version 2.1 of the License, or (at your option) any later version.
00013  *
00014  * FFmpeg is distributed in the hope that it will be useful,
00015  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00016  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00017  * Lesser General Public License for more details.
00018  *
00019  * You should have received a copy of the GNU Lesser General Public
00020  * License along with FFmpeg; if not, write to the Free Software
00021  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00022  */
00023 
00030 #ifndef AVCODEC_MPEGAUDIOTAB_H
00031 #define AVCODEC_MPEGAUDIOTAB_H
00032 
00033 #include <stdint.h>
00034 #include "mpegaudio.h"
00035 
00036 #define SQRT2 1.41421356237309514547
00037 
00038 static const int costab32[30] = {
00039     FIX(0.54119610014619701222),
00040     FIX(1.3065629648763763537),
00041 
00042     FIX(0.50979557910415917998),
00043     FIX(2.5629154477415054814),
00044     FIX(0.89997622313641556513),
00045     FIX(0.60134488693504528634),
00046 
00047     FIX(0.5024192861881556782),
00048     FIX(5.1011486186891552563),
00049     FIX(0.78815462345125020249),
00050     FIX(0.64682178335999007679),
00051     FIX(0.56694403481635768927),
00052     FIX(1.0606776859903470633),
00053     FIX(1.7224470982383341955),
00054     FIX(0.52249861493968885462),
00055 
00056     FIX(10.19000812354803287),
00057     FIX(0.674808341455005678),
00058     FIX(1.1694399334328846596),
00059     FIX(0.53104259108978413284),
00060     FIX(2.0577810099534108446),
00061     FIX(0.58293496820613388554),
00062     FIX(0.83934964541552681272),
00063     FIX(0.50547095989754364798),
00064     FIX(3.4076084184687189804),
00065     FIX(0.62250412303566482475),
00066     FIX(0.97256823786196078263),
00067     FIX(0.51544730992262455249),
00068     FIX(1.4841646163141661852),
00069     FIX(0.5531038960344445421),
00070     FIX(0.74453627100229857749),
00071     FIX(0.5006029982351962726),
00072 };
00073 
00074 static const int bitinv32[32] = {
00075     0,  16,  8, 24,  4,  20,  12,  28,
00076     2,  18, 10, 26,  6,  22,  14,  30,
00077     1,  17,  9, 25,  5,  21,  13,  29,
00078     3,  19, 11, 27,  7,  23,  15,  31
00079 };
00080 
00081 
00082 static int16_t filter_bank[512];
00083 
00084 static int scale_factor_table[64];
00085 #ifdef USE_FLOATS
00086 static float scale_factor_inv_table[64];
00087 #else
00088 static int8_t scale_factor_shift[64];
00089 static unsigned short scale_factor_mult[64];
00090 #endif
00091 static unsigned char scale_diff_table[128];
00092 
00093 /* total number of bits per allocation group */
00094 static unsigned short total_quant_bits[17];
00095 
00096 /* signal to noise ratio of each quantification step (could be
00097    computed from quant_steps[]). The values are dB multiplied by 10
00098 */
00099 static const unsigned short quant_snr[17] = {
00100      70, 110, 160, 208,
00101     253, 316, 378, 439,
00102     499, 559, 620, 680,
00103     740, 800, 861, 920,
00104     980
00105 };
00106 
00107 /* fixed psycho acoustic model. Values of SNR taken from the 'toolame'
00108    project */
00109 static const float fixed_smr[SBLIMIT] =  {
00110     30, 17, 16, 10, 3, 12, 8, 2.5,
00111     5, 5, 6, 6, 5, 6, 10, 6,
00112     -4, -10, -21, -30, -42, -55, -68, -75,
00113     -75, -75, -75, -75, -91, -107, -110, -108
00114 };
00115 
00116 static const unsigned char nb_scale_factors[4] = { 3, 2, 1, 2 };
00117 
00118 #endif /* AVCODEC_MPEGAUDIOTAB_H */