static protected String toDecFrac(double duration) {
		long n, d, ggT;
		d = (long) 26240 * 12;
		n = (long) (duration * d);
		ggT = ggT(d, n);
		d /= ggT;
		n /= ggT;
		if (n == 1) {
			if (d == 1) {
				return "";
			} else if (d == 2)
				return "/";
		}
		if (d == 1)
			return Integer.toString((int) n);
		else if (d == 2)
			return Integer.toString((int) n) + "/";
		return Integer.toString((int) n) + "/" + Integer.toString((int) d);
	}