I think I could add something here. If your video is really clean without lots of random motion and noise, it can compress very well on DVD. However, Blu-ray really is cheap these days. When I started out writing DVD software, DVD-Rs were $10 each. DVD recorders were $500. Now, Blu-ray recorders are around $200 and Blu-ray recording media is around a dollar. Blu-ray is your best bet for getting HD material to look like HD. However, really well produced video compress very well and can upscale well on DVD. It’s just a lot more work.
Brad Wright is software engineer, so often hard to figure out what he is talking about. He is always happy to explain answers further.