Blur settings on export

I shoot all of my organ recital dvds on Sony EX cameras 1920x1080 25i

A lot of the footage is of cathedral architecture involving lots of fine horizontal lines. This all looks fine in HD but when converted to SD for the dvd I get flickering on the fine detail during camera tilts and pans. I have tried both using Premiere and AVIsynth HD2SD for the down conversion both with the same results. In the end I add blur in the export settings (4 vertical works best) to take the edge off the detail. How do other editors get round this problem?

Richard Knight