Yes, you need to insert a bland DVD disc, either DVD-r or DVD+r is ok, before you burn movie to DVD. Generally speaking, DVD-r is more compatible than DVD+r.

A DVD has a higher capacity than a CD

A DVD-r is a Digital video disc that can be recorded only once. A DVD-rw is a disc that can be recorded more than once

Huge bigger than you' ll ever need

a DVD plus r means ,dvd+r, it is a variant of common dvd, which can be written once . after it has been written, the data ot content can not be changed. if you want to change it, u need a dvd+rw, that means, u can write more than once