What type of DVD formats or manufacturer(s) do motion pictures use? Most are dual layer today, but what type of DVD is of the highest quality that movies use to distribute with? No matter how I look at these DVDs, they are nameless.

They're not a type you can buy, like DVD-R. They're replicated, from a pressed gold master. The file format is MPEG2 (bad choice, IMHO, because a temporal codec makes scratches and skips much harder for the player to deal with.)