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93 lines
2.4 KiB
C
93 lines
2.4 KiB
C
/*
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* mpeg audio layer 2 tables. Most of them come from the mpeg audio
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* specification.
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*
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* Copyright (c) 2000, 2001 Gerard Lantau.
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*
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* The licence of this code is contained in file LICENCE found in the
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* same archive
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*/
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#define SQRT2 1.41421356237309514547
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static const int costab32[30] = {
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FIX(0.54119610014619701222),
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FIX(1.3065629648763763537),
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FIX(0.50979557910415917998),
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FIX(2.5629154477415054814),
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FIX(0.89997622313641556513),
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FIX(0.60134488693504528634),
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FIX(0.5024192861881556782),
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FIX(5.1011486186891552563),
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FIX(0.78815462345125020249),
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FIX(0.64682178335999007679),
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FIX(0.56694403481635768927),
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FIX(1.0606776859903470633),
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FIX(1.7224470982383341955),
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FIX(0.52249861493968885462),
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FIX(10.19000812354803287),
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FIX(0.674808341455005678),
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FIX(1.1694399334328846596),
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FIX(0.53104259108978413284),
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FIX(2.0577810099534108446),
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FIX(0.58293496820613388554),
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FIX(0.83934964541552681272),
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FIX(0.50547095989754364798),
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FIX(3.4076084184687189804),
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FIX(0.62250412303566482475),
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FIX(0.97256823786196078263),
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FIX(0.51544730992262455249),
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FIX(1.4841646163141661852),
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FIX(0.5531038960344445421),
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FIX(0.74453627100229857749),
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FIX(0.5006029982351962726),
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};
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static const int bitinv32[32] = {
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0, 16, 8, 24, 4, 20, 12, 28,
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2, 18, 10, 26, 6, 22, 14, 30,
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1, 17, 9, 25, 5, 21, 13, 29,
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3, 19, 11, 27, 7, 23, 15, 31
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};
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static INT16 filter_bank[512];
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static int scale_factor_table[64];
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#ifdef USE_FLOATS
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static float scale_factor_inv_table[64];
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#else
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static INT8 scale_factor_shift[64];
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static unsigned short scale_factor_mult[64];
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#endif
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static unsigned char scale_diff_table[128];
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/* total number of bits per allocation group */
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static unsigned short total_quant_bits[17];
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/* signal to noise ratio of each quantification step (could be
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computed from quant_steps[]). The values are dB multiplied by 10
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*/
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static unsigned short quant_snr[17] = {
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70, 110, 160, 208,
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253, 316, 378, 439,
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499, 559, 620, 680,
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740, 800, 861, 920,
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980
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};
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/* fixed psycho acoustic model. Values of SNR taken from the 'toolame'
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project */
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static const float fixed_smr[SBLIMIT] = {
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30, 17, 16, 10, 3, 12, 8, 2.5,
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5, 5, 6, 6, 5, 6, 10, 6,
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-4, -10, -21, -30, -42, -55, -68, -75,
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-75, -75, -75, -75, -91, -107, -110, -108
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};
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static const unsigned char nb_scale_factors[4] = { 3, 2, 1, 2 };
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