3 channels confirmed for Freeview HD

It's to do with the way the English regional opts are inserted into Mux 1 at the regional centres. Mux 1 is distributed nationally, with network BBC 1 as a sustaining service in there, at a fixed rate of 4.5 Mb/s. In addition a 10 Mb/s feed of BBC 1 network is also sent.

Normal operation is that the regional centre recodes either its own output (during opt outs) or the 10 meg BBC 1 Network feed to 4.5 Mb/s and 'cut&pastes' that over the network BBC 1 in Mux 1. That's why BBC 1 is fixed at 4.5.

If a BBC regional centre should burn down etc, at least Energis or whoever can patch Mux 1 directly to the regional Txs, and restore all BBC services (inc BBC1)

The nations because they have their own pres/playout, code and mux locally, so BBC 1 there is stat muxed with 2,3,N24 etc. I think the same is actually the case for the London region too ?

and IIRC the plan is eventually to have the regions send their show back to London ITV style so it can be statmuxed with the rest of the channels on each transmitter

Ah I see, that explains it. I never knew that was how it is setup. I was assuming it was similar to ITV1 where the opting out was done from London/Leeds. Thanks

The project is called CCM - Centralised Coding & Multplexing. Each of the regional centres will send their output across virtual circuits on the Raman network to the CCM nodes, these will then do the multiplexing. Since they have all the uncompressed feeds they can statmux them properly.

The name is a bit misleading though, as the system is not centralised to a single point. The system is distributed so that should the London node stop working then the multiplexing will be picked up by systems elsewhere in the country.

Yep - the RAMAN network, although introduced in quite a low-key manner, is a major innovation. Every regional, national or network centre can now talk to any other centre without having to worry about circuits between them. The old mix of 140Mbs PAL and 34Mbs Compressed Component circuits has been replaced with 270Mbs Uncompressed Component circuits - which are capable of carrying high quality Dirac Pro compressed HD content. A very big change - accompanied by almost no fanfare.

oh so they *ARE* using dirac after all.

In other HD news, the head of BBC HD has decided that from this weekend the channel will remove it's DOG for drama and films (a bit like BBC Four) and will make it as transparent as possible for all other programmes, after loads of posts about it on her blog.

Dirac Pro is being used to route HD signals around the SD fibre infrastructure at TVC I believe (so live shows from TC1,4 and 8 may well have been carried via a Dirac Pro conversion) - and CAN be used to send stuff around the Raman network between BBC production centres, though I don't know how much this happens.

It was also used in Beijing to convert BBC unilateral SD circuits to HD - so that location reporters could be in-vision in HD rather than SD. (The circuits were booked in Beijing before BBC HD had been approved - so the BBC could not pay for HD circuits)

Has PQ done any live HD yet?

Great News.

Although DOGs don't bother me so much, I still don't understand the argument about it being needed for identification purposes. Surely the EPG does a good job, and the analouge channels don't have them - and according to this logic they should be the channels with the most need for on screen junk.

100% transparent or is that not possible?

Also after politicians and Media Guardian were moaning yesterday about 10% of the country only getting half the Freeview channels - and missing out on Five, it's been "announced" today that Five will move to Mux B as regions switch to digital. Which we all knew about anyway.

However, they say due to HD taking over it's only a temporary arrangement, so it looks like in the end BBC will get PSB1 to themselves and the three commercial channels will have to share PSB2.