Fourth terrestrial HD channel 'in 2010'

Ofcom has confirmed that capacity will be available for a fourth high definition channel to launch on digital terrestrial television in July 2010.

The media regulator said it would start accepting applications for services to use the capacity on multiplex B - which is being reconfigured as digital switchover happens across the UK - immediately. HD services from the BBC, ITV and Channel 4 will become available on digital terrestrial starting next March, and although a full rollout will not be complete until 2012, it is possible that the use of spare frequencies in major metropolitan areas could bring Freeview HD to key cities in 2009 and 2010.

In its technical assessment, Ofcom offered three scenarios for the availability of capacity depending on which profile of DVB-T2, the next-generation digital terrestrial transmission standard, is adopted. This will determine the bitrate within which all services on the multiplex must operate. The scenarios consist of a lower case, in which 34Mbps of capacity is available, 30 of which would be available for video streams, a central case where there is 36Mbps of total capacity and 32.3 available for HD video streams, and an upper case with the same amount of total capacity but more space for video because a more efficient codec is used for the provision of audio. The regulator described the lower case as "unlikely" and the central case as "conservative", suggesting that the use of the more efficient HE-AAC audio codec and advanced statistical multiplexing equipment running video streams at an average bitrate of 8.4Mbps was achievable by 2010.

As such, Ofcom said it was "satisfied that it will be possible to support 4 HD services on multiplex B with acceptable quality before the end of 2010... based on the assumption that the latest generation H.264 video encoding and statistical multiplexing equipment will be used when the fourth service is launched and a DVB-T2 profile which provides in excess of 34Mbps is adopted".

Applications to use the capacity for a fourth public service HD channel will be accepted until February 19 next year. Five is eligible to apply, as are ITV, Channel 4, S4C and Teletext.