I've used the following for high-action/motion video... looks just as good as the source file (using HALF KDVD TEMPLATE, CQ=90), but your milage may vary:
LoadPlugin("V:\encoding\MPEG2DEC.dll")
LoadPlugin("V:\encoding\fluxsmooth.dll")
LoadPlugin("V:\encoding\blockbuster.dll")
LoadPlugin("V:\encoding\legalclip.dll")
mpeg2source("x:\xxxxx\xxxxxx.xxx")
LegalClip()
BilinearResize(xxx,xxx,xxx,xxx)
FluxSmooth()
Blockbuster( method="noise", detail_min=1, detail_max=10, variance=1 )
AddBorders(xx,xx,xx,xx)
LegalClip()