For both DISH and DirecTV, the 1080p content is from their respective 'On-Demand' services.
DirecTV's is only delivered through the network, not satellite. DISH has both satellite download and IP/network capabilities for their OnDemand service.
The IPTV that Dish Offers is not considered On Demand, it is downloaded by choice from the user. Anything from Movies and More and the VOD in the EPG is On Demand and is pushed to the receiver without any intervention from the user. -- BetaTech