Watching F1 today, I was imagining what it'd be like if it went HD. But that would need ITV to broadcast HD to get any benefit. Which got me thinking a bit more. For something like SkyHD, all existing SD channels will need to be rebroadcast as well. Will these be in MPEG4 for compatibility with the STB? Also, how trivial would it be for a channel to slowly introduce a limited HD service? Kind of like how ITV did with Dolby Surround in the late 90's? Broadcast a brief thing at the beginning 'broadcast in High Definition where available'. Then if you have HD you see the program in HD. If you have SD, you start to see these notices and it might encourage take-up of HD services. I think they do something similar in Japan. There are BS Hivision programs but not all the programs on a channel are HD, some are simulcast SD.