IF it's a standard optical pc drive of some sort there should be a emergency release hole somewhere under the tray depending on which drive it is.
you'll need a stiff wire or pin or something that fits in and if it's strong enough it should let you physically push open the drive mechanism through the hole.
If it's some kind of set top dvd recorder some have keystrokes that work when you turn on the box, some MAY have the eject hole but I don't have any that support it, all my PC drives have one as far as I'm aware.
Good luck with it.
If you tell us which drive it is somebody can probably give you more detailed help.