Why a burned dvd-r wont work in a dvd player?

[AlyshaeTigs]

I just bought some blank dvd roms so that I could burn some videos onto them. I burned some videos onto 2 discs off of itunes but when I put them in the dvd player to watch them it wont work I can only watch them when they are in the computer. I googled it and it says that I have to finalize the dvd... but how do you finalize a dvd off of itunes? are there any other reasons why it wont work?