Technology of satellite television
Direct broadcast via satellite
Television receive-only
Early history of satellite television
Beginning of the satellite TV industry
TVRO/C-band satellite era
1990s to present of satellite television
History of Freesat
Video on demand
Reception equipment of satellite television
Technical details of satellite television

Freeview (UK)

Freeview is the United Kingdom's digital terrestrial television platform. It is operated by DTV Services Ltd, a joint venture between the BBC, ITV, Channel 4, Sky and transmitter operator Arqiva. It was launched in 2002, taking over the licence from ITV Digital which collapsed that year. The service provides consumer access via an aerial to the six DTT multiplexes covering the United Kingdom. In April 2014 it had some 60 TV channels, 26 digital radio channels, 10 HD channels, six text services, 11 streamed channels, and one interactive channel. A number of new HD channels launched in 2014, from a new group of multiplexes awarded to Arqiva. The new HD channels were launched in selected areas on 10 December 2013 with a further roll-out during 2014.

Although all pay channels had been closed down on ITV Digital, many free-to-air channels continued broadcasting, including the five analogue channels and digital channels such as ITV2, ITN News Channel, S4C2, TV Travel Shop and QVC. With the launch of Freeview other channels were broadcast free-to-air, such as: Sky Travel, UK History, Sky News, Sky Sports News, The Hits (now 4Music) and TMF (now Viva) were available from the start. BBC Four and the interactive BBC streams were moved to multiplex B. Under the initial plans, the two multiplexes operated by Crown Castle would carry eight channels altogether. The seventh stream became shared by UK Bright Ideas and Ftn which launched in February 2003. The eighth stream was left unused until April 2004 when the shopping channel Ideal World launched on Freeview. There are now 14 streams carried by the two multiplexes, with Multiplex C carrying 6 streams, and Multiplex D carrying 8. It has recently[when?] been announced that more streams are now available on the multiplexes, and that bidding is under way.

The Freeview service broadcasts free-to-air television channels, radio stations and interactive services from the existing public service broadcasters. Channels on the service include the BBC, ITV, Channel 4 and Channel 5 terrestrial channels, as well as their digital services. In addition, channels from other commercial operators, such as Sky and UKTV, are available, as well as radio services from a number of broadcasters.

A subscription-based DTT service, Top Up TV, launched in March 2004. The Top Up TV service was not connected with the Freeview service, but ran alongside it on the DTT platform and was included in the Freeview EPG; programmes could be received on some Freeview set-top boxes and televisions equipped with a card slot or CI slot. Top Up TV was replaced in 2006, by a service that did not run on Freeview equipment.

To ensure provision of audio description, broadcasters typically use the AAC codec. Hardware restrictions allow only a single type of audio decoder to operate at any one time, so the main audio and the audio description must use the same encoding family for them to be successfully combined at the receiver. In the case of BBC HD, the main audio is coded as AAC-LC and only the audio description is encoded as HE-AAC. Neither AAC nor Dolby Digital Plus codecs are supported by most home AV equipment, which typically accept Dolby Digital or DTS, leaving owners with stereo, rather than surround sound, output. Transcoding from AAC to Dolby Digital or DTS and multi-channel output via HDMI was not originally necessary for Freeview HD certification. As of June 2010 the DTG D-Book includes the requirement for mandatory transcoding when sending audio via S/PDIF, and for either transcoding or multi-channel PCM audio when sending it via HDMI in order for manufacturers to gain Freeview HD certification from April 2011. Thus equipment sold as Freeview HD before April 2011 may not deliver surround sound to audio equipment (some equipment may, but this is not mandatory); later equipment must be capable of surround sound compatible with most suitable audio equipment.

It combines catch-up TV (BBC iPlayer, ITV Hub, All 4, My5 and UKTV Play), on demand and live television on a variety of TV and set-top boxes, via the userís standard broadband Internet connection. The technology is an open standard, but with prominent Freeview Play branding. The service launched in October 2015 on compliant equipment, initially 2015 Panasonic TV receivers and Humax set-top boxes, including existing models with a software update. Other manufacturers were announcing new models "later this [2015] year". The 2017 specification for Freeview Play includes support for HDR video using Hybrid Log-Gamma (HLG), when playing on demand broadband content.