MegaPEG does an excellent job of HD downconversion for DVD encoding. Because our image processing pipeline is so flexible, finding a combination of de-interlacing and filtering that provides a clean picture at 720x480 or 720x576 is easy.
To illustrate my point I've posted a pair of DVD-rez versions downconverted from Mako Shark Club Jacket. Link to
DVD from HD source material.
I'll be posting a more detailed description of Mako a bit later, but if you look at the sample you will see how well MegaPEG performs on a mixture of CG and organic material.