libavcodec/mpegaudiotab.h

   1 /*
   2  * mpeg audio layer 2 tables. Most of them come from the mpeg audio
   3  * specification.
   4  *
   5  * Copyright (c) 2000, 2001 Fabrice Bellard.
   6  *
   7  * The licence of this code is contained in file LICENCE found in the
   8  * same archive
   9  */
  10
  11 /**
  12  * @file mpegaudiotab.h
  13  * mpeg audio layer 2 tables.
  14  * Most of them come from the mpeg audio specification.
  15  */
  16
  17 #define SQRT2 1.41421356237309514547
  18
  19 static const int costab32[30] = {
  20     FIX(0.54119610014619701222),
  21     FIX(1.3065629648763763537),
  22
  23     FIX(0.50979557910415917998),
  24     FIX(2.5629154477415054814),
  25     FIX(0.89997622313641556513),
  26     FIX(0.60134488693504528634),
  27
  28     FIX(0.5024192861881556782),
  29     FIX(5.1011486186891552563),
  30     FIX(0.78815462345125020249),
  31     FIX(0.64682178335999007679),
  32     FIX(0.56694403481635768927),
  33     FIX(1.0606776859903470633),
  34     FIX(1.7224470982383341955),
  35     FIX(0.52249861493968885462),
  36
  37     FIX(10.19000812354803287),
  38     FIX(0.674808341455005678),
  39     FIX(1.1694399334328846596),
  40     FIX(0.53104259108978413284),
  41     FIX(2.0577810099534108446),
  42     FIX(0.58293496820613388554),
  43     FIX(0.83934964541552681272),
  44     FIX(0.50547095989754364798),
  45     FIX(3.4076084184687189804),
  46     FIX(0.62250412303566482475),
  47     FIX(0.97256823786196078263),
  48     FIX(0.51544730992262455249),
  49     FIX(1.4841646163141661852),
  50     FIX(0.5531038960344445421),
  51     FIX(0.74453627100229857749),
  52     FIX(0.5006029982351962726),
  53 };
  54
  55 static const int bitinv32[32] = {
  56     0,  16,  8, 24,  4,  20,  12,  28,
  57     2,  18, 10, 26,  6,  22,  14,  30,
  58     1,  17,  9, 25,  5,  21,  13,  29,
  59     3,  19, 11, 27,  7,  23,  15,  31
  60 };
  61
  62
  63 static int16_t filter_bank[512];
  64
  65 static int scale_factor_table[64];
  66 #ifdef USE_FLOATS
  67 static float scale_factor_inv_table[64];
  68 #else
  69 static int8_t scale_factor_shift[64];
  70 static unsigned short scale_factor_mult[64];
  71 #endif
  72 static unsigned char scale_diff_table[128];
  73
  74 /* total number of bits per allocation group */
  75 static unsigned short total_quant_bits[17];
  76
  77 /* signal to noise ratio of each quantification step (could be
  78    computed from quant_steps[]). The values are dB multiplied by 10
  79 */
  80 static const unsigned short quant_snr[17] = {
  81      70, 110, 160, 208,
  82     253, 316, 378, 439,
  83     499, 559, 620, 680,
  84     740, 800, 861, 920,
  85     980
  86 };
  87
  88 /* fixed psycho acoustic model. Values of SNR taken from the 'toolame'
  89    project */
  90 static const float fixed_smr[SBLIMIT] =  {
  91     30, 17, 16, 10, 3, 12, 8, 2.5,
  92     5, 5, 6, 6, 5, 6, 10, 6,
  93     -4, -10, -21, -30, -42, -55, -68, -75,
  94     -75, -75, -75, -75, -91, -107, -110, -108
  95 };
  96
  97 static const unsigned char nb_scale_factors[4] = { 3, 2, 1, 2 };
  98