src/third_party/opus/silk/resampler_rom.c

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#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

/* Filter coefficients for IIR/FIR polyphase resampling     *
 * Total size: 179 Words (358 Bytes)                        */

#include "resampler_private.h"

/* Matlab code for the notch filter coefficients: */
/* B = [1, 0.147, 1];  A = [1, 0.107, 0.89]; G = 0.93; freqz(G * B, A, 2^14, 16e3); axis([0, 8000, -10, 1]) */
/* fprintf('\t%6d, %6d, %6d, %6d\n', round(B(2)*2^16), round(-A(2)*2^16), round((1-A(3))*2^16), round(G*2^15)) */
/* const opus_int16 silk_resampler_up2_hq_notch[ 4 ] = { 9634,  -7012,   7209,  30474 }; */

/* Tables with IIR and FIR coefficients for fractional downsamplers (123 Words) */
silk_DWORD_ALIGN const opus_int16 silk_Resampler_3_4_COEFS[ 2 + 3 * RESAMPLER_DOWN_ORDER_FIR0 / 2 ] = {
    -20694, -13867,
       -49,     64,     17,   -157,    353,   -496,    163,  11047,  22205,
       -39,      6,     91,   -170,    186,     23,   -896,   6336,  19928,
       -19,    -36,    102,    -89,    -24,    328,   -951,   2568,  15909,
};

silk_DWORD_ALIGN const opus_int16 silk_Resampler_2_3_COEFS[ 2 + 2 * RESAMPLER_DOWN_ORDER_FIR0 / 2 ] = {
    -14457, -14019,
        64,    128,   -122,     36,    310,   -768,    584,   9267,  17733,
        12,    128,     18,   -142,    288,   -117,   -865,   4123,  14459,
};

silk_DWORD_ALIGN const opus_int16 silk_Resampler_1_2_COEFS[ 2 + RESAMPLER_DOWN_ORDER_FIR1 / 2 ] = {
       616, -14323,
       -10,     39,     58,    -46,    -84,    120,    184,   -315,   -541,   1284,   5380,   9024,
};

silk_DWORD_ALIGN const opus_int16 silk_Resampler_1_3_COEFS[ 2 + RESAMPLER_DOWN_ORDER_FIR2 / 2 ] = {
     16102, -15162,
       -13,      0,     20,     26,      5,    -31,    -43,     -4,     65,     90,      7,   -157,   -248,    -44,    593,   1583,   2612,   3271,
};

silk_DWORD_ALIGN const opus_int16 silk_Resampler_1_4_COEFS[ 2 + RESAMPLER_DOWN_ORDER_FIR2 / 2 ] = {
     22500, -15099,
         3,    -14,    -20,    -15,      2,     25,     37,     25,    -16,    -71,   -107,    -79,     50,    292,    623,    982,   1288,   1464,
};

silk_DWORD_ALIGN const opus_int16 silk_Resampler_1_6_COEFS[ 2 + RESAMPLER_DOWN_ORDER_FIR2 / 2 ] = {
     27540, -15257,
        17,     12,      8,      1,    -10,    -22,    -30,    -32,    -22,      3,     44,    100,    168,    243,    317,    381,    429,    455,
};

silk_DWORD_ALIGN const opus_int16 silk_Resampler_2_3_COEFS_LQ[ 2 + 2 * 2 ] = {
     -2797,  -6507,
      4697,  10739,
      1567,   8276,
};

/* Table with interplation fractions of 1/24, 3/24, 5/24, ... , 23/24 : 23/24 (46 Words) */
silk_DWORD_ALIGN const opus_int16 silk_resampler_frac_FIR_12[ 12 ][ RESAMPLER_ORDER_FIR_12 / 2 ] = {
    {  189,  -600,   617, 30567 },
    {  117,  -159, -1070, 29704 },
    {   52,   221, -2392, 28276 },
    {   -4,   529, -3350, 26341 },
    {  -48,   758, -3956, 23973 },
    {  -80,   905, -4235, 21254 },
    {  -99,   972, -4222, 18278 },
    { -107,   967, -3957, 15143 },
    { -103,   896, -3487, 11950 },
    {  -91,   773, -2865,  8798 },
    {  -71,   611, -2143,  5784 },
    {  -46,   425, -1375,  2996 },
};