You know you're truly obsessed with the subject of your next blog when you're still discussing transmission compression standards with an official from the communications sector regulator at a time on a Friday afternoon when most sensible people are in the pub.
That is exactly what I did last week though. It was all done in an effort to get an insight - for the purposes of the article that you are reading right now - into the debate about whether or not DVB-T2 is the correct solution for getting free-to-air PSB high definition services on DTT sooner rather than later.
As succintly as I can, here is the background:
DVB-T2 is a new transmission coding standard and an extension of the DVBT one currently used in the UK. It is expected to deliver an increase of at least 30% in the capacity of a DTT multiplex. It is so new that approval as a standard hasn't been agreed yet, although that should happen in the next couple of months.
In order to shoehorn HD onto Freeview, Ofcom proposes to reorganise the channels on the current DTT multiplexes in order to free up a multiplex. This multiplex, for those of you that are interested, is Multiplex B which is currently operated by the BBC. It will be upgraded with the MPEG-4 compression and DVB-T2 transmission standards. This will result in space potentially being available for four free-to-air PSB HD channels by 2012.
The plan to shuffle the current multiplexes means Ofcom won't have to release any of the spectrum freed up by digital switchover for HD services, allowing it to auction those off to the highest bidder.
The HD channels that will launch will be decided by a 'beauty contest' in which each of the public service broadcasters - BBC, ITV, C4 and Five - sets out its proposals for how it will use the 'blocks' of available spectrum. Ofcom will pick the winners.
The regulator expects the first HD services will start being made available from 2009 and 2010 in the regions that are switching completely from analogue to digital television.
Which all sounds great, right? However, when Ofcom released this plan - in its consultation document The Future of DTT- there was lots of 'feedback' from various interested parties. It seems that the technical feasibility is being called into question.
The Digital Television Group (DTG), which represents broadcasters and manufacturers, said, in a strongly worded response, that DVB-T2 simply won't be ready in time.
Policy Tracker sums it up:
The DTG response claims Ofcom has relied on what it calls "forward-looking assumptions" about the evolution of MPEG4 and "the possible commercial evolution of the embryonic DVB-T2 standard," and goes on to say "these should be evaluated very carefully when framing any future decisions about allocations and service mixes". The group says the Ofcom proposals are "critically dependent on assumptions about the timing of DVB-T2, it timing and its affordability." As DTG's members will be making the DVB-2 equipment, the group claims to have a better understanding of the issue than Ofcom.
The other grumble is that Ofcom's proposal means that 'only' four channels will be available in HD from switchover in 2012. Some people think there should be five. The union, Bectu, for one, wasn't too happy, accusing Ofcom of treachery.
And neither was the DTG, which wants Ofcom to release an extra couple of frequencies so that all five PSB channels can be launched simultaneously. These frequencies would come from the block being freed up by switchover but could be returned at some point.
Which leads me neatly back to my chat with the official from the communications sector regulator. Mr Philip Rutnam, partner in the spectrum policy group at Ofcom, said in response to the above:
"We are very confident that DVBT2 will be adopted. We are very confident that consumer equipment embodying both MPEG4 and DVBT2 could be brought to market first towards the end of 2009 and then in larger and larger volumes from 2010 onwards."
Asked why he was so confident, he replied
"Talking to a range of manufacturers interested in expanding the market, seeing the progress that has been made in DVB and the knowledge which has been reinforced by what many others have said to us that the clear lead in terms of the standards that will be used creates a virtuous circle in terms of people designing and developing, bringing to market equipment that meets those standards. Resolving and reducing uncertainly helps to create momentum."
As for handing out extra spectrum, Rutnam seemed a little puzzled. He said:
"I don't understand the proposal that they're making. If they're saying that Digital Dividend Review (DDR) spectrum should be the spectrum that's used to offer HD services to DTT viewers - DDR spectrum won't be available nationwide until the end of 2012. And no new DTT multiplex is likely to be able to offer services until 2013, maybe later. Under our proposal, HD services will actually start being available on DTT from 2009 or early 2010. If you use the DDR spectrum it won't be until three years later."
From what I know of it, if they did use the freed up spectrum - the digital dividend review (DDR) spectrum - it would also be quite difficult to get the same level of coverage as the existing DTT multiplexes do. And especially with existing television aerials. Roughly 5% of homes would need to buy new aerials as well as new set-top boxes.
I've looked at both arguments and each has its merits. I couldn't tell you which was right or wrong though. That is for you to decide.
What surprises me most is that decisions are being pushed through so quickly. With something as potentially important as this - both from a technology viewpoint and because this is taxpayer's money - surely it would be better to take a step back, look at all the options, wait for the correct technology to be proven and then decide. As it stands, we could have free-to-air HD by next year. Which seems very soon indeed.
Interested parties can hear more about this debate at the DTG's annual industry summit next Friday (7 March).
What is your view on Ofcom's plan for HD on DTT? Have your say below.