The BBC currently have just a few encoders for the HD multiplex, but to switch fully regional it would require one for every regional variant combination of BBC1 and ITV, of which there are many and which don't necessarily overlap, along with all the fibre backhaul to and from each studio centre, transmitter, encoder etc... Plus the backup routes for the feed etc.. Not a simple, or cheap task.
Yep - though AIUI because PSB3 is fully statmuxed, doesn't there already have to be an encoder for BBC One HD, BBC Two HD, CBBC HD, ITV HD, C4 HD and C5 HD for every ITV / C4 regional variation combo - to allow for full statmuxing? (ITV and C4 regional advertising also has an impact)
Theres also the matter of whether it is worth all the effort to do it before the regional news studios, and ENG kit, are all fully-HD.
This is the bigger argument. It's currently very difficult to argue for the additional cost to provide SD content via an HD platform. Annoying as the 'Switch to SD for your BBC One reigon' is, the costs of providing full HD opt-chains for all the SD-only regions is still difficult to justify. Yes - there is a quality improvement by upconverting SD to HD (though the state of some English regions studio cameras may mean you wouldn't want to experience them in all their glorious SD upconverted to HD glory...) but with the current BBC finances - it's difficult to justify.
However - as BBC regional centres inevitably upgrade from their (often first gen) 16:9 SD gear as it reaches the end of its life, HD gear will inevitably replace it, and the arguments to provide HD regions IN HD will have a lot more validity. However the big question is when the BBC will do 'Vilor for TV'. Plymouth's HD upgrade was a lesson in the real cost of in-situ HD upgrades, and it was not a low cost exercise. I think there will be a pause on any other HD upgrades until IP can be properly evaluates.
It's worth the effort to at least have nice clean native 270 meg SD upscaled to HD for the regional news, and of course remove the requirement to have to change channel from HD to SD.
You may think that. Others disagree. Spending millions of pounds to provide a short-term upgrade to existing SD regional centres to provide SD upconverted pictures is a difficult thing to justify, particularly if you are then going to have to replace the gear any way as you upgrade the regional operations to HD.
By the way, no upgrades to the CCM centres to transmitter circuits are required. If the Beeb were to follow ITV's regional opting architecture, fewer HD distribution and contribution circuits would be required, I can't believe they're not thinking along those lines ( no pun intended)
No - that's true - because PSB 3 is PSB 3 - it leaves CCM to go to the transmitters as a 40.25Mbs transport stream anyway. However other infrastructure in the BBC is changing (the move from Raman to BT for instance...)