Transcoding for a vertical display

I've been assigned the task of transcoding 16:9 for a flatscreen that is to be turned on it's side. To tackle this problem I've rotated the image to fit into the "portrait" format, and exported to ProRes. Here's the kicker, the client has requested DVD's. When I transcode from Compressor to the DVD format, I get terrible interlacing.

I understand that when creating a DVD, De-interlacing is not necessary, however that coupled with the flat screen being on its side, I'm not really sure how to tackle this. Is it because I've rotated the image that I'm getting this? Any help is very much appreciated.

With respect,

Josh