Test transmissions for ITV HD last week were broadcast as H.264 video encapsulated within an H.222 data stream rather than an ordinary video stream. The data stream can not be seen using traditional commonly-owned equipment, though Digital Spy forum members receiving digital satellite television on their home computer were able to view it.
ITV has since confirmed that its HD service will be available only to those using Freesat receivers.
"ITV HD is only available through Freesat, so you’ll need a satellite dish and either a TV with freesat HD built in (available soon), or a Freesat HD digital box connected to an HD ready TV," the broadcaster confirmed on its website.
Freesat - which will be formally launched today - is a joint venture between the BBC and ITV, and the exclusivity of ITV will be a unique selling point.
However, Seetha Kumar, head of HDTV at BBC Vision, today confirmed the corporation's high definition channel, BBC HD, would not become "Freesat exclusive".
In a general post regarding BBC HD on the BBC Internet Blog, she wrote: "With Freesat today and Freeview in the future, the next phase promises to be just as busy (as earlier developments in HD).
"Incidentally, I'd like to squash the mounting speculation in some blogs: BBC HD will not be exclusive to Freesat. We are and will remain platform neutral."