ffmpeg.js/libswresample/resample.c
/**
 * 0th order modified bessel function of the first kind.
 */
0th order modified bessel function of the first kind.
0th order modified bessel function of the first kind .
static double bessel(double x){
    double v=1;
    double lastv=0;
    double t=1;
    int i;
    static const double inv[100]={
 1.0/( 1* 1), 1.0/( 2* 2), 1.0/( 3* 3), 1.0/( 4* 4), 1.0/( 5* 5), 1.0/( 6* 6), 1.0/( 7* 7), 1.0/( 8* 8), 1.0/( 9* 9), 1.0/(10*10),
 1.0/(11*11), 1.0/(12*12), 1.0/(13*13), 1.0/(14*14), 1.0/(15*15), 1.0/(16*16), 1.0/(17*17), 1.0/(18*18), 1.0/(19*19), 1.0/(20*20),
 1.0/(21*21), 1.0/(22*22), 1.0/(23*23), 1.0/(24*24), 1.0/(25*25), 1.0/(26*26), 1.0/(27*27), 1.0/(28*28), 1.0/(29*29), 1.0/(30*30),
 1.0/(31*31), 1.0/(32*32), 1.0/(33*33), 1.0/(34*34), 1.0/(35*35), 1.0/(36*36), 1.0/(37*37), 1.0/(38*38), 1.0/(39*39), 1.0/(40*40),
 1.0/(41*41), 1.0/(42*42), 1.0/(43*43), 1.0/(44*44), 1.0/(45*45), 1.0/(46*46), 1.0/(47*47), 1.0/(48*48), 1.0/(49*49), 1.0/(50*50),
 1.0/(51*51), 1.0/(52*52), 1.0/(53*53), 1.0/(54*54), 1.0/(55*55), 1.0/(56*56), 1.0/(57*57), 1.0/(58*58), 1.0/(59*59), 1.0/(60*60),
 1.0/(61*61), 1.0/(62*62), 1.0/(63*63), 1.0/(64*64), 1.0/(65*65), 1.0/(66*66), 1.0/(67*67), 1.0/(68*68), 1.0/(69*69), 1.0/(70*70),
 1.0/(71*71), 1.0/(72*72), 1.0/(73*73), 1.0/(74*74), 1.0/(75*75), 1.0/(76*76), 1.0/(77*77), 1.0/(78*78), 1.0/(79*79), 1.0/(80*80),
 1.0/(81*81), 1.0/(82*82), 1.0/(83*83), 1.0/(84*84), 1.0/(85*85), 1.0/(86*86), 1.0/(87*87), 1.0/(88*88), 1.0/(89*89), 1.0/(90*90),
 1.0/(91*91), 1.0/(92*92), 1.0/(93*93), 1.0/(94*94), 1.0/(95*95), 1.0/(96*96), 1.0/(97*97), 1.0/(98*98), 1.0/(99*99), 1.0/(10000)
    };
    x= x*x/4;
    for(i=0; v != lastv; i++){
        lastv=v;
        t *= x*inv[i];
        v += t;
        av_assert2(i<99);
    }
    return v;
}
static double bessel ( double x ) { double v = 1 ; double lastv = 0 ; double t = 1 ; int i ; static const double inv [ 100 ] = { 1.0 / ( 1 * 1 ) , 1.0 / ( 2 * 2 ) , 1.0 / ( 3 * 3 ) , 1.0 / ( 4 * 4 ) , 1.0 / ( 5 * 5 ) , 1.0 / ( 6 * 6 ) , 1.0 / ( 7 * 7 ) , 1.0 / ( 8 * 8 ) , 1.0 / ( 9 * 9 ) , 1.0 / ( 10 * 10 ) , 1.0 / ( 11 * 11 ) , 1.0 / ( 12 * 12 ) , 1.0 / ( 13 * 13 ) , 1.0 / ( 14 * 14 ) , 1.0 / ( 15 * 15 ) , 1.0 / ( 16 * 16 ) , 1.0 / ( 17 * 17 ) , 1.0 / ( 18 * 18 ) , 1.0 / ( 19 * 19 ) , 1.0 / ( 20 * 20 ) , 1.0 / ( 21 * 21 ) , 1.0 / ( 22 * 22 ) , 1.0 / ( 23 * 23 ) , 1.0 / ( 24 * 24 ) , 1.0 / ( 25 * 25 ) , 1.0 / ( 26 * 26 ) , 1.0 / ( 27 * 27 ) , 1.0 / ( 28 * 28 ) , 1.0 / ( 29 * 29 ) , 1.0 / ( 30 * 30 ) , 1.0 / ( 31 * 31 ) , 1.0 / ( 32 * 32 ) , 1.0 / ( 33 * 33 ) , 1.0 / ( 34 * 34 ) , 1.0 / ( 35 * 35 ) , 1.0 / ( 36 * 36 ) , 1.0 / ( 37 * 37 ) , 1.0 / ( 38 * 38 ) , 1.0 / ( 39 * 39 ) , 1.0 / ( 40 * 40 ) , 1.0 / ( 41 * 41 ) , 1.0 / ( 42 * 42 ) , 1.0 / ( 43 * 43 ) , 1.0 / ( 44 * 44 ) , 1.0 / ( 45 * 45 ) , 1.0 / ( 46 * 46 ) , 1.0 / ( 47 * 47 ) , 1.0 / ( 48 * 48 ) , 1.0 / ( 49 * 49 ) , 1.0 / ( 50 * 50 ) , 1.0 / ( 51 * 51 ) , 1.0 / ( 52 * 52 ) , 1.0 / ( 53 * 53 ) , 1.0 / ( 54 * 54 ) , 1.0 / ( 55 * 55 ) , 1.0 / ( 56 * 56 ) , 1.0 / ( 57 * 57 ) , 1.0 / ( 58 * 58 ) , 1.0 / ( 59 * 59 ) , 1.0 / ( 60 * 60 ) , 1.0 / ( 61 * 61 ) , 1.0 / ( 62 * 62 ) , 1.0 / ( 63 * 63 ) , 1.0 / ( 64 * 64 ) , 1.0 / ( 65 * 65 ) , 1.0 / ( 66 * 66 ) , 1.0 / ( 67 * 67 ) , 1.0 / ( 68 * 68 ) , 1.0 / ( 69 * 69 ) , 1.0 / ( 70 * 70 ) , 1.0 / ( 71 * 71 ) , 1.0 / ( 72 * 72 ) , 1.0 / ( 73 * 73 ) , 1.0 / ( 74 * 74 ) , 1.0 / ( 75 * 75 ) , 1.0 / ( 76 * 76 ) , 1.0 / ( 77 * 77 ) , 1.0 / ( 78 * 78 ) , 1.0 / ( 79 * 79 ) , 1.0 / ( 80 * 80 ) , 1.0 / ( 81 * 81 ) , 1.0 / ( 82 * 82 ) , 1.0 / ( 83 * 83 ) , 1.0 / ( 84 * 84 ) , 1.0 / ( 85 * 85 ) , 1.0 / ( 86 * 86 ) , 1.0 / ( 87 * 87 ) , 1.0 / ( 88 * 88 ) , 1.0 / ( 89 * 89 ) , 1.0 / ( 90 * 90 ) , 1.0 / ( 91 * 91 ) , 1.0 / ( 92 * 92 ) , 1.0 / ( 93 * 93 ) , 1.0 / ( 94 * 94 ) , 1.0 / ( 95 * 95 ) , 1.0 / ( 96 * 96 ) , 1.0 / ( 97 * 97 ) , 1.0 / ( 98 * 98 ) , 1.0 / ( 99 * 99 ) , 1.0 / ( 10000 ) } ; x = x * x / 4 ; for ( i = 0 ; v != lastv ; i ++ ) { lastv = v ; t *= x * inv [ i ] ; v += t ; av_assert2 ( i < 99 ) ; } return v ; }
0th order modified bessel function of the first kind.
0th order modified bessel function of the first kind .