mpegaudiotab.h

杜比AC-3编码解码器（参考程序）

};

/* signal to noise ratio of each quantification step (could be
   computed from quant_steps[]). The values are dB multiplied by 10 
*/
static unsigned short quant_snr[17] = { 
     70, 110, 160, 208,
    253, 316, 378, 439,
    499, 559, 620, 680, 
    740, 800, 861, 920, 
    980
};


/* total number of bits per allocation group */
static unsigned short total_quant_bits[17];

/* encoding tables which give the quantization index. Note how it is
   possible to store them efficiently ! */
static const unsigned char alloc_table_0[] = {
 4,  0,  2,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 
 4,  0,  2,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 
 4,  0,  2,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 
 4,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 16, 
 4,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 16, 
 4,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 16, 
 4,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 16, 
 4,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 16, 
 4,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 16, 
 4,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 16, 
 4,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 2,  0,  1, 16, 
 2,  0,  1, 16, 
 2,  0,  1, 16, 
 2,  0,  1, 16, 
};

static const unsigned char alloc_table_1[] = {
 4,  0,  2,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 
 4,  0,  2,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 
 4,  0,  2,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 16, 
 4,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 16, 
 4,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 16, 
 4,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 16, 
 4,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 16, 
 4,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 16, 
 4,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 16, 
 4,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 16, 
 4,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 3,  0,  1,  2,  3,  4,  5, 16, 
 2,  0,  1, 16, 
 2,  0,  1, 16, 
 2,  0,  1, 16, 
 2,  0,  1, 16, 
 2,  0,  1, 16, 
 2,  0,  1, 16, 
 2,  0,  1, 16, 
};

static const unsigned char alloc_table_2[] = {
 4,  0,  1,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 
 4,  0,  1,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 
 3,  0,  1,  3,  4,  5,  6,  7, 
 3,  0,  1,  3,  4,  5,  6,  7, 
 3,  0,  1,  3,  4,  5,  6,  7, 
 3,  0,  1,  3,  4,  5,  6,  7, 
 3,  0,  1,  3,  4,  5,  6,  7, 
 3,  0,  1,  3,  4,  5,  6,  7, 
};

static const unsigned char alloc_table_3[] = {
 4,  0,  1,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 
 4,  0,  1,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15, 
 3,  0,  1,  3,  4,  5,  6,  7, 
 3,  0,  1,  3,  4,  5,  6,  7, 
 3,  0,  1,  3,  4,  5,  6,  7, 
 3,  0,  1,  3,  4,  5,  6,  7, 
 3,  0,  1,  3,  4,  5,  6,  7, 
 3,  0,  1,  3,  4,  5,  6,  7, 
 3,  0,  1,  3,  4,  5,  6,  7, 
 3,  0,  1,  3,  4,  5,  6,  7, 
 3,  0,  1,  3,  4,  5,  6,  7, 
 3,  0,  1,  3,  4,  5,  6,  7, 
};

static const unsigned char alloc_table_4[] = {
 4,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
 4,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 
 4,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 
 4,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 
 3,  0,  1,  3,  4,  5,  6,  7, 
 3,  0,  1,  3,  4,  5,  6,  7, 
 3,  0,  1,  3,  4,  5,  6,  7, 
 3,  0,  1,  3,  4,  5,  6,  7, 
 3,  0,  1,  3,  4,  5,  6,  7, 
 3,  0,  1,  3,  4,  5,  6,  7, 
 3,  0,  1,  3,  4,  5,  6,  7, 
 2,  0,  1,  3, 
 2,  0,  1,  3, 
 2,  0,  1,  3, 
 2,  0,  1,  3, 
 2,  0,  1,  3, 
 2,  0,  1,  3, 
 2,  0,  1,  3, 
 2,  0,  1,  3, 
 2,  0,  1,  3, 
 2,  0,  1,  3, 
 2,  0,  1,  3, 
 2,  0,  1,  3, 
 2,  0,  1,  3, 
 2,  0,  1,  3, 
 2,  0,  1,  3, 
 2,  0,  1,  3, 
 2,  0,  1,  3, 
 2,  0,  1,  3, 
 2,  0,  1,  3, 
};

const unsigned char *alloc_tables[5] = 
{ alloc_table_0, alloc_table_1, alloc_table_2, alloc_table_3, alloc_table_4, };

/* fixed psycho acoustic model. Values of SNR taken from the 'toolame'
   project */
const float fixed_smr[SBLIMIT] =  {
    30, 17, 16, 10, 3, 12, 8, 2.5,
    5, 5, 6, 6, 5, 6, 10, 6,
    -4, -10, -21, -30, -42, -55, -68, -75,
    -75, -75, -75, -75, -91, -107, -110, -108
};

const unsigned char nb_scale_factors[4] = { 3, 2, 1, 2 };