On 2 July, the regulator revealed that two channel slots will be made available to provide HD services on Freeview. They are expected to start in 2009 in regions that have switched from analogue to digital television.
The capacity is being created by a reorganisation of the existing multiplexes and an upgrade of multiplex B to new coding standards DVB-T2 and MPEG-4.
Based on the premise that compression standards will continue to improve, a third and fourth channel are expected to be made available between 2009 and just after digital switchover.
One of the services will be BBC HD. Ofcom, in a statutory notice, has invited the other qualifying broadcasters, ITV (including STV and UTV), Channel 4, Five, S4C and Teletext, to apply for the rest of the spectrum.
Ofcom expects broadcasters to provide any of the following either separately or in combination:
A simulcast service (with regional elements replaced by other programming);
A non-simulcast service (same content on a different schedule);
Overnight downloads between 11pm and 6am in HD or SD.
Broadcasters will not have to fill a full 24-hour period with just one service and will be able to share or rent out blocks of capacity.
Ofcom's pitching criteria include efficient use of spectrum, high-quality programming and original UK content. Each submitted application will cost£15,000.
The application process ends on 13 August. Ofcom will issue draft licences at the end of October and full licences at the end of 2008.