Example:
15 b = 2.054388e-10 DVD (2 layers, 1 side)
1 b = 1.369592e-11 DVD (2 layers, 1 side) | 1 DVD (2 layers, 1 side) = 7.301444e+10 b
Conversion Steps:
15 × (1 / 7.301444e+10) = 2.054388e-10