}
		if ah != 0 && ah != al+1 {
			return FormatError("bad successive approximation values")
		}
	}

	// mxx and myy are the number of MCUs (Minimum Coded Units) in the image.
	h0, v0 := d.comp[0].h, d.comp[0].v // The h and v values from the Y components.
	mxx := (d.width + 8*h0 - 1) / (8 * h0)
	myy := (d.height + 8*v0 - 1) / (8 * v0)