I'm using both old analog converted material (connect my old 8mm pass-through my new DV camera) and new DV material during editing.
Once rendered to a low bitrate (VCD or SVCD) I get many macroblocks on the digital source scenes while none on the convereted analog scenes. Note that when high bitrating (DVD template) the digital material is amazingly clear.

What is the cause?
I read once that the 4:1:1 of the DV has to do. How can I improve?

Thanks