The obvious answer is people just reupload stuff they have downloaded, as is without doing anything to it. Nobody rips their own DVDs esp not porn. Nobody buys DVDs anymore. Most movies are downloaded from some porn site, not ripped from real DVDs. Plus a DVD iso is around 4.7GB, way too big for just 1 movie. I don't think DVD is even HD. I know BluRay is HD & those are 25GB. And most people just watch it on their computer, not burn to DVDs. Esp porn, since there is soooooo much of it.