One of the wires at the back of the deck should be labeled parking brake. That is the wire that controls video playback. Just ground that wire and you should be good to go.
Usually the wire is pink or orange ..anyway ..you can follow it to the break ....and see what color it has..and when you ground it to the body of the car it will bypass this function ..
If you are not comfortable with switching wires..just pull the break one step ...enough to trick it to think it is on ..but not enough to affect the function ..or the break to be on ..

Unfortunately it's not that simple : the drive lock is done thru an electronic command - the player gets this information from the ECM, not just a simple Park wire.
To make it work the entire wiring of the player must be modified - a fiddly job that must be left to a pro shop (if you can find one that is willing to do it - illegal and severely punishable). Unless of course you want to do it yourself and risk frying the entire electronics of the car.