Some doubts about DVD format and 16:9, 4:3,...

[LowCost]

Hi!!! I just have some doubts about DVD format specs.
A DVD frame has a resolution of 720x576 pixels in PAL format, and 720x480 in NTSC.
So if the maximum horizontal resolution is 720 pixels, a 16:9 movie frame should have a vertical height of 405 lines. What do they do with the 171 (PAL) or 75 (NTSC) remaining lines? Do they fill it with black? Or do they encode every frame at 720x576/480 and then my 16:9 TV vertically compresses the image to fit all these lines in the virtually correct 405-lines vertical space?

Thank you!

[Simon T]

720*576, you're right. The other lines are used by the black lines. Actually, the 16/9 format is nothing else than 4/3 but with black bars on both sides on the screen.