static int find_group3_syncmarker(GetBitContext *gb, int srcsize)
{
    unsigned int state = -1;
    srcsize -= get_bits_count(gb);
    while(srcsize-- > 0){
        state+= state + get_bits1(gb);
        if((state & 0xFFF) == 1)
            return 0;
    }
    return -1;
}