What is the best way to downscale 1080p video to a suitable format for DVD, while retaining as much quality as possible? I currently have Final Cut Pro X and Compressor 4 at my disposal (both at versions 1.2). Will this be enough, or will additional software be necessary?
You can do it with the software you have. Here is a tutorial from Larry Jordan. The one point he doesn't show is that you want to set your resize filter to Best. In Compressor 4 this is under the Frame Controls tab, next to the Encoder tab that Larry shows. Not sure where it is in Compressor 4.1