I know that SVCDs reside on CD-R's wih a 700MB size limit and DVDs reside on discs with a much higher capacity.

I know that DVD discs spin at a higher speed than CD(-R)(W)'s.

When I make SVCDs that include fast pans, they appear blocky while commercial DVDs don't appear blocky at all.

Is it an inferior MPEG-2 encoder that we use on our PCs as opposed to Hollywood (et al)?

Is it because a DVD spits out way more information (spins faster) than a mere SVCD?

Is it just because a DVD is 720 x 480 at 60 fields per second while a SVCD is just 2/3 of this: 480 x 480 at 60 fields per second?

Any light shed will be welcome!

Sean