static void calculate_comb_factor_yuy2_vektor( tvtime_t *tvtime, uint8_t *curframe,
                                             int instride,
                                             int frame_height,
                                             int width )
{
    /* we have yv12 format - to detect the pulldown we only use
       luminance (Y) data, so we only need the first frame_height * width
       bytes of the frame */
    int i, j, top, mid, bot, wdt, dj, wdt2;
    tvtime->combfactor = 0;
    for(i=50; i<frame_height-50; i+=4)
    {
        wdt2 = 2*width;
        wdt = wdt2*i;
        for(j=50; j<width-50; j++)
        {
            dj = j*2+wdt;
            top = curframe[dj-(wdt2)];
            mid = curframe[dj];
            bot = curframe[dj+(wdt2)];
            tvtime->combfactor += ((top - mid) * (bot - mid) - ( ((top - bot)^2) >> 7 ));
        }
    }
    tvtime->combfactor /= (43 * frame_height);
}