Example:
15 DVD (2 layers, 2 sides) = 2.190433e+12 b
1 DVD (2 layers, 2 sides) = 1.460289e+11 b | 1 b = 6.84796e-12 DVD (2 layers, 2 sides)
Conversion Steps:
15 × (1.460289e+11 / 1) = 2.190433e+12