Authoring a final SD DVD with both SD and HD video source files? | DVD Studio Pro V4

Hello:

I'm experience with shooting/editing/compression etc. with FCP, Apple Compressor, etc., but very new with DVD Studio Pro - very frustrating!

My question: I authored an HD DVD using both SD and HD videos with a menu format; all the videos play fine in the "simulate" preview mode AND... the DVD plays exactly like it's supposed to on my 2010 Macbook Pro.

PROBLEM: I tried watching the DVD in a DVD player and... ERROR MESSAGE.

And so... I'm hearing HD DVD is a "dead" format, Blu Ray won the war... and Apple DVD Studio Pro does NOT support Blu Ray (is that right?)

MY QUESTION: Is there a way to simply change the "preferences" tab on my DVD Studio project to SD, and all the files will then be rendered to a DVD that is playable on any fairly modern DVD player?

Thank you

M