What is the best file format to use for a blank DVD please?

Hi I use Cyberlink Power Director V 13 and I used to use Mpeg-2 but have been told the quality wouldn't be very good.

I'd like to do a HD video on Cyberlink Power Director 13, but the DVD is for my parents, and I don't think they have a HD TV.

Advice needed please?

Thanks.

What is the best file format to use for a blank DVD please?