Aspect ratio for 1920x1080 clips rendered for DVD?

dalemccl wrote on 10/19/2010, 7:23 PM
Note: I mis-typed the title and typed 1902 where I meant 1920. Tried to fix in EDIT but it still shows up in the topic list as 1902.

My source clips are AVCHD 1920x1080i NTSC from a Sony camcorder. Sometimes I want to end up with a standard-def DVD, so in Movie Studio I render with MainConcept MPEG-2 using the "DVD Architect NTSC Widescreen Video Stream" template. After selecting this template, it shows that it is 720x480. I always thought that was the right ratio for DVD.

But recently I read somewhere that with 1920x1080 video clips, an aspect ratio of 704x480 should be used when rendering for DVD, instead of 720x480. Is that true? Why?