static void vc1_loop_filter(uint8_t* src, int step, int stride, int len, int pq)
{
    int i;
    int filt3;

    for(i = 0; i < len; i += 4){
        filt3 = vc1_filter_line(src + 2*step, stride, pq);
        if(filt3){
            vc1_filter_line(src + 0*step, stride, pq);
            vc1_filter_line(src + 1*step, stride, pq);
            vc1_filter_line(src + 3*step, stride, pq);
        }
        src += step * 4;
    }
}