For 3D you must switch it on in the service menu, and then it becomes selectable as one of the map orientations:
Direction of Travel
North
3D

Check you have the right firmware loaded, on the Settings screen, top right corner should show 4-1/00

As for videos, just connect an AV cable to the AV-IN port of the TV tuner.
As digital TV is replacing analog TV, the analog TV tuners should be getting cheaper and cheaper as 2nd hand units