How to delete info off a dvd-r disc

Question

the dvd-r disc contians 2 videos and it said, it is protected by wriiten stuff

Answer 1

you can only erase a dvd-rw not dvd-r. once you write to it, its there forever

Answer 2

You can't delete it because it is not a DVD-RW. When you use a DVD or CD like this, all info on that disc will become read only.It means that you can only view the file and can only be edited if you copy it into your computer. Next time, get a DVD-RW if you want to edit or erase the contents inside it.  

Answer 3

If it's a DVD+/-R, you can't delete it.  It can be written to until the capacity is reached, but once written the to the disc, there's no way to remove that info.

Only DVD+/-RW discs can be rewritten (rewriting with either other data or 'empty' information when it's deleted).