DVD-5 is a single layer DVD with 4.7GB of storage. It is the most common type of DVD format.

DVD-9 is a double layer DVD with 8.5GB of storage. It is also very common for a feature length video.

Now, what about DVD-R and dual layer DVD-R (DL DVD-R)? These are blank media formats for duplication only, which is burning with DVD recorders. DVD-5 and DVD-9 are created by molding from glass masters, which does not involve any blank media. This is also known as replication.

Tomorrow we’ll tackle the issues that everyone asks: Are replicated discs better than duplicated discs?