Ofcom should hold off auctioning spectrum freed by digital TV switchover until it is sure its proposed technology upgrade will work.

If it doesn't, industry fears Freeview will be crippled as other platforms roll-out HD channels with which the digital terrestrial TV service will not have the spectrum space to compete.

Last week, Ofcom announced that it and the BBC Trust planned to work together on a major upgrade of the digital terrestrial TV platform to make space for high-definition services.

Ofcom chief executive Ed Richards said: "This is a once in a lifetime opportunity to upgrade digital terrestrial television. It offers benefits fro broadcasters - who will be able to launch new services without using any new spectrum - and viewers - who will have access to new channels and services on free to air."

Mr Richards basically embraced the same line he took last year - that is, he believed there was enough room for HD on digital terrestrial TV without giving broadcasters access to any spectrum freed by digital switchover.

The proposed upgrade would require a change in transmission mode back from the more stable 16QAM used by Freeview to the 64QAM originally used by ITV Digital, and the adoption of next-generation DDT standards for transmission (DVB-T2) and compression (MPEG-4).

The change in transmission mode (to 64QAM) will increase capacity on the Freeview platform by around 20 per cent, said Ofcom.

MPEG-4 compression would, it added, be up to twice as efficient as the current MPEG-2 standard, while the new European transmission standard (DVB-T2) will, it continued, increase capacity by at least another 30 per cent.

On top of that, broadcasters will be required to make the most efficient use of current broadcast standards.

The change would also require clearing one of the six multiplexes used to broadcast digital terrestrial TV (Multiplex B) and upgrading it to use the new technologies.

Ofcom said it believed HD services on DTT should operate initially at 720p to ensure three HD services could fit on Multiplex B from launch in late 2008 or early 2010, with a fourth HD service added in 2011 or 2012.

"We would envisage this moving towards the 1080p format over time as efficiency gains allow," Ofcom said. "However, we also note that the broadcasters should have as much flexibility as possible and that there may be occasions when the use of 1080i is more appropriate. We are therefore minded to allow all three formats to be used."

Industry is fairly relaxed about the move to more efficient MPEG-4 compression and even the mode change back to 64QAM - technology has advanced and stability will no longer be the issue that it was with ITV Digital, ERT Weekly was told.

However, DVB-T2 is still an unknown quantity. That standard has not been field tested because it has still to be ratified and the silicon and hardware to be developed, as Humax commercial director Graham North pointed out. Although he is sure it will work.

At Panasonic, marketing director Andrew Denham was not overly concerned either that no other country had yet decided to adopt DVB-T2. He pointed out that the UK was the first to use MPEG-2 and DVB, too. Others will follow suit.

But the fact it is not yet ready has raised concerns about Ofcom's suggestion - picked up by the national press - that viewers will be able to get HD on Freeview in digitally-switched regions as early as 2009.

Adrian Northover Smith, who is head of products and services development at Sony, called them "challenging time lines".
Humax's Mr North thought 2010 a more likely timeframe.

Ofcom's faith in new technology is touching, but there is no getting away from the fact that it is deciding the future of Britain's digital terrestrial TV service based on an untested standard and is leaving the platform with no fallback position if things do not go according to plan.

It is this that prompted Mr Northover Smith to say: "I think Ofcom should hold off the spectrum auctions until they make sure the technology works."

At Humax, Mr North pointed out that in France the Government had earmarked additional spectrum so that all the main channels on its terrestrial TV service could be broadcast in HD. Alas, here, "We would rather get the money in the bank."

The online magazine for the broadcasting industry Digital Spy also has its doubts.

It repeated industry doubts about the untested DVB-T2 standard. While Ofcom stated that early products could be ready for the end of next year, Digital TV Group chief Dermot Nolan told Digital Spy that he believed late 2010 was more likely. Then it would rely on "firms stumping up cash for a product that may or may not sell".

He said: ""It is more likely towards the end of 2010 or in 2011. At the moment it is not a paper standard - it's to be confirmed.
"(The standard) has to be agreed then go to the ETSI (the European regulator), then people have to decide to industrialise it... people have to make investment decisions about this."

The launch of Freeview's free-to-view satellite counterpart Freesat, a joint BBC ITV venture due to launch here in spring, could also cause Freeview an additional headache.

As Mr Northover Smith pointed out, it will certainly raise the bar on high-definition broadcasting.

"The Freeview platform will now have competition," he said, and a competitor that is not constrained by bandwidth in the amount of free HD programming it can offer.

It will change consumer expectations and inevitably lead to greater demand for more HD on Freeview. The digital terrestrial TV platform, following Ofcom's decision to auction off spectrum, will, of course, not be able to oblige. That is, unless another jump in technology rides to the rescue. 

The fear that four high-definition channels on Freeview will not be enough to attract consumers is widespread.

As Digital Spy pointed out, if manufacturers are not convinced of the viability of HD on the platform - the Digital TV Group's Dermot Nolan had already alluded to a "product that may or may not sell" - they may be reluctant to make equipment for consumer use.

Mr Nolan told Digital Spy: "You need to have a credible HDTV offer. "By the time this is launched satellite will probably have about 23 or 24 (HD) channels.

"There should be a critical mass of HD channels (on Freeview) and that should be about 12." The Digital TV Group put forward a plan to do this last month that would require two more multiplexes to be added for new HD channels, most likely from spectrum freed by switchover.

At Humax, Mr North was also concerned that changing [Multiplex B]  specifications in the middle of switchover could lead to confusion among some consumers. Viewers who want to access the Freeview HD channels will have to buy new TV equipment. As he pointed out, it could be a delicate issue for switchover lead body Digital UK.

As Digital Spy reported, BT has already highlighted the issue "of accelerated equipment obsolescence and the prospect of a potential second switchover".