High-definition television in Australia

On 1 January 2002, the ABC began a prime-time simulcast of ABC's Sydney station ABN, except that it had no watermark and was upconverted from standard definition to 1080i high definition. On 1 January 2005 it changed to 576p to accommodate the launch of new channel ABC2 and gradually expanded its operating hours.

On 1 January 2008, the ABC's high definition simulcast was rebranded as ABC HD, relaunching as a high definition multichannel with its own logo and branding. The channel was also enhanced to 720p to mark the start of native high-definition content.

Throughout its multichannel era, ABC HD continued providing a high definition simulcast of ABN Sydney. As a result, viewers outside of New South Wales would see Sydney-based news bulletins and other localised content. The purpose of this as of 2008, was to provide high-definition versions of ABC1 shows when available (Prior to this, the broadcaster relied on regulation exemptions that allowed it to meet a high-definition quota using content upscaled from standard definition).

There were exceptions to the ABC1 simulcast: During the 2008 Summer Paralympics in Beijing, ABC HD became a dedicated sports broadcaster, simulcasting the dedicated coverage on ABC2 for most of the day. The 2009 VFL Grand Final was shown exclusively live on ABC HD. For a time up until ABC HD branding ceased, ABC HD screened a "7:30 Select" national highlights package instead of the Sydney version of Stateline.

On 10 June 2010, ABC HD's unique branding was replaced with that of ABC1, reverting the channel to an ABN Sydney simulcast. ABC HD ceased being a simulcast of ABC1 from 6 July 2010 in Tasmania and the ACT; 7 July 2010 in Queensland, South Australia, Western Australia and Northern Territory; and on 8 July 2010 in Victoria and New South Wales, all replaced by a looped pre-launch promotion for ABC News 24 on channel 24. This made ABC the second broadcaster in Australia to permanently discontinue the high definition simulcast of its main channel, following the removal of Ten HD to create Ten's former sports and now entertainment channel One in 2009.

ABC Director of Television Richard Finlayson confirmed that the ABC will recommence simulcasting in HD in June 2016. However, in contrast to its past, ABC HD will provide regional-specific simulcasting, not just a nationwide simulcast of ABN Sydney. As a result, ABC News 24 will be reduced to a standard definition broadcast.

On 6 December 2016, the ABC HD recommenced simulcasting in high definition, upgrade to 1080i high-definition format via Freeview and Optus D1. As a result, ABC News 24 was reduced to a standard definition broadcast on channel 24.

In 2004, after the 2001 introduction of digital terrestrial television in Australia, the Seven Network began a part-time high definition simulcast on digital channel 70 under the name 7 HD Digital. This simulcast showcased native high definition content alongside standard definition services on Seven. During the times that native high definition content was unavailable for simulcasting, a promo loop that showcased extracts from a variety of Seven's programs was broadcast.

7HD was officially announced on 15 September 2007, with the Seven West Media announcing their intention to start a high definition multichannel, that was initially expected to launch in December 2007. However, 7HD became the first Free-to-air commercial television channel introduced to metropolitan areas since 1988, when it launched prior on 15 October 2007, with 25th Hour being the first program broadcast at 10:30pm.

The channel replaced Seven's existing high definition service 7 HD Digital, a part-time simulcast of its standard definition and analogue services. Due to an amendment of the Broadcasting Services Act 1992 in 2006, the Broadcasting Legislation Amendment (Digital television) Act 2006, television networks are now permitted to launch digital multichannels, provided that they are broadcast exclusively in high definition. The channel expanded its broadcast schedule on 10 December 2007 to include daytime programming which had previously been a full simulcast of the main channel. 7HD breakaway programming ceased transmission on Sunday 4 October 2009 in preparation for the launch of 7TWO a few weeks later on 1 November. 7HD then returned to being a full high definition simulcast of Seven, before finally being replaced by 7mate on 25 September 2010.

On 10 May 2016, 7HD returned as a high definition simulcast on channel 70.

From the launch of digital TV on 1 January 2001, the Nine Network's high definition service, a simulcast of its standard definition and analogue services, was heavily simulcasting Nine's standard definition content upconverted to HD. From 2002, this was interspersed with a loop of high definition demonstration material during business hours, for viewing in the showrooms of television retailers, at the conclusion of an equivalent service by Network Ten.

2002 saw the first revenue-generating broadcast in native HD in Australia, with the drama Judging Amy. Nine increased its native HD output in the lead-up to the commencement of the HD quota on 1 July 2003, from which point it broadcast a minimum of 1,040 hours of native HD content per year. The largest portion of this was The Today Show.

9HD was officially announced as a part-time (or "breakaway") multichannel on 27 September 2007, to replace the Nine Network's existing high definition simulcast service through the use of an amendment to the Broadcasting Services Act 1992 in 2006. The Broadcasting Legislation Amendment (Digital television) Act 2006 permitted television networks to launch digital multichannels, provided that they are broadcast exclusively in high definition.

Although originally expected to be the first free-to-air commercial television channel introduced to metropolitan areas since 1988, meant that 9HD was not the first high definition multichannel in Australia. Following this, plans for a November launch in 2007 were postponed until 2008. On 10 March 2008, PBL Media announced that it would launch the channel on 17 March 2008 at 10:30pm, with its first program, Nightline.

The re-branded 9HD officially commenced transmission on 17 March 2008 from PBL Media's four metropolitan owned-and-operated stations, TCN Sydney, GTV Melbourne, QTQ Brisbane and NTD Darwin, in addition to WIN Corporation's two metropolitan stations NWS Adelaide, and STW Perth as well as on its regional stations RTQ Queensland, WIN southern New South Wales, VTV Victoria, and TVT Tasmania. The first official program on launch night began at 19:00, Nine News's flagship daily main national nightly television news bulletin program Nine Television News.

All 9HD breakaway programming ceased transmission on Sunday 2 August 2009 in preparation for the launch of GO! (now 9Go!) on 9 August. As a result, 9HD became a full simulcast of Nine's main channel.

9HD was replaced by the 9Gem multichannel on 26 September 2010, which unlike the previous incarnation, was a full-time breakaway and branded separately (with one exception being the London Olympics). This removed the HD simulcast of Channel Nine entirely to allow a third channel to fit on Nine's DVB-T multiplex (due to technical and regulatory limitations). As a result, Nine lost all youth, news and comedy content in HD, but instead screened female, crime and lifestyle content on its only HD facility.

For the purposes of some sport such as cricket, GEM was still used on an occasional basis to broadcast HD under the Wide World of Sports brand, though not necessarily as a simulcast with Nine. As such, this was generally limited to events outside of prime time, while those with more prominence continued to be shown on the Nine Network.

On 26 November 2015, Nine recommenced simulcasting in HD on channel 90. As a result, 9Gem was moved to channel 92 and reduced to standard definition. Then in June 2019, metro viewers were given access to 9 Gem in HD on Channel 95, replacing an advertising channel.

This revival marked 9HD's switch to H.264/MPEG-4 AVC broadcasting, allowing the broadcaster to operate at full quality in 1920x1080i50 resolution using a lower bitrate than in 2007. This gives the network the ability to provide all the other multichannel services launched since 2009, such as 9Go!, at the same time.

From the revamp of its production and circle logo and of the slogan Seriously Ten on 1 February 2001, this was interspersed with a loop of high definition demonstration material during business hours, for viewing in the showrooms of television retailers, at the conclusion of an equivalent service by Network Ten.

Ten HD was officially announced on 14 September 2007, to replace Network Ten's existing high definition service, a simulcast of its standard definition and analogue services, through the use of an amendment to the Broadcasting Services Act 1992 in 2006. The Broadcasting Legislation Amendment (Digital Television) Act 2006 permitted television networks to launch digital multichannels, provided that they are broadcast exclusively in high definition.

Although originally expected to be the first free-to-air commercial television channel introduced to metropolitan areas since 1988, the surprise launch of Seven Media Group's HD offering, 7HD, on 15 October 2007, two months before transmissions were scheduled to begin, meant that Ten HD was launched as the second high-definition multichannel in Australia. PBL Media announced the creation of a similar multichannel, 9HD, on 27 September, which was launched on 17 March 2008.

Ten's parent company, and shareholder in metropolitan ratings system OzTAM, Ten Network Holdings Limited, began discussions with the ratings system operator to have digital multichannels, such as Ten HD and ABC2, included in television ratings for the first time on 17 September 2007. As well as this, on the same day, it was announced that the national weekend editions of Ten News would be timeshifted from Ten onto Ten HD, an hour delayed at 6 pm, to directly compete with Seven News and National Nine News. This would have seen Ten News formally broadcast at 6 pm for the first time since 1992, however, the timeslot was later amended to 5.30 pm.

In preparation for the launch of Ten HD, Ten's digital terrestrial channel line-up was updated on 19 November 2007, with changes consisting of LCN1 redirecting Network Ten's current high-definition simulcast. Following this, on 21 November 2007, Ten Network Holdings Limited announced that it would launch the channel on 16 December 2007 at 5.00 pm, with the first program, Totally Wild.

Ten HD officially commenced transmission on 16 December 2007 from the network's five metropolitan owned-and-operated stations in Sydney, Melbourne, Brisbane, Adelaide, and Perth. Prior to the official launch, at 5.00 pm the first program, Totally Wild, was broadcast. Following this, for the first time since 1992, Ten News and Sports Tonight were broadcast in direct competition with Seven News and National Nine News, timeshifted by thirty minutes to 5.30 pm and 6.00 pm respectively.

The first official program on launch night began at 8.30 pm, the 2001 movie Black Hawk Down. This was followed by Bon Jovi's Lost Highway Tour at 11.30 pm and Video Hits Presents: The Music of Supernatural at 12.25 am. Video Hits Up-Late marked the end of the first night of transmission for Ten HD at 12.50 am.

In the lead-up to the opening night, the channel promised up to eleven hours of time-shifted programming from Ten in addition to fifty hours of exclusive programming, which included live sport, entertainment, films, documentaries, science fiction and news. This consisted of six movies per week, in addition to National Geographic documentaries in the afternoon, from 3pm to 5pm, music-oriented programming following the Sunday Night Movie, along with a primetime breakaway schedule on Thursdays and from 10.30 pm to 11.30 pm Monday to Wednesday.

In addition to high definition broadcasting on channel 1, a standard definition simulcast of Ten HD was provided on channel 11 as Ten SD2.

From 2009, commercial networks in Australia were allowed to broadcast a standard definition subchannel. Rather than introduce a new digital service, Ten decided to relaunch Ten HD as a sports-only channel, to be named One HD (now One), and use its standard definition simulcast on channel 11 to broadcast a standard definition simulcast called One SD. Before One HD's official launch, most breakaway programming shown on Ten HD ceased from 1 January 2009, and only showed a high-definition broadcast of the existing Ten digital service, along with a few sports-based breakaway programs. Ten HD officially shut down on 25 March 2009, with One HD launching the following day.

After the Nine Network restarted broadcasting 9HD in November 2015, Ten confirmed that it was working on rebroadcasting Ten HD. However, they did not put a time frame on it, stating that they are "working through some technical and rights issues". On 11 February 2016, some smart TVs began receiving notification messages advising of Ten HD through a "ghost broadcast" that soon disappeared.

Ten later recommenced simulcasting in high definition on 2 March 2016 on channel 13 from 3pm, in time for the 2016 season of the Virgin Australia Supercars Championship. As a result, One was reduced to a standard definition broadcast on both channel 1 and channel 12.

Ten uses MPEG-4 technology to broadcast the channel.

The SBS HD multichannel was launched on 14 December 2006. It broadcasts identical programming to SBS, but in 1080i HD via Freeview and Optus D1. Also in 2018, SBS Viceland was given HD Access on Channel 31. On 1 July 2019, Channel 32 was converted into a HD World Movies in 1080i HD.

The Freeview brand was launched in November 2008 with teaser commercials promising 15 channels in 2009. The first new "Freeview" channel started on 26 March 2009 with Network Ten's One sports channel. Further advertising began on 26 April 2009, with the first Freeview certified devices appearing in retailers from May 2009. In June 2010, the second phase of devices, marked as "Freeview EPG" devices, became available in retail stores, designed to work with the newly launched interactive EPG built on MHEG-5. This Freeview EPG will cease operating on 24 November 2017.

Foxtel has been carrying HD channels since 2008. As of 2016 it has over 20 HD channels, a mix of basic and premium subscription, free-to-air and free-to-view services.

HD broadcasts are received using the Foxtel IQ3 service or a Foxtel HD+ receiver. A selection of HD push-video on demand content is also available through Foxtel Anytime on Foxtel HD+ receivers.

ABC News, 7mate, 7HD, 9HD, Ten HD, SBS HD along with regional networks WIN HD, Prime7HD and 9HD with NBN are available unencrypted and without subscription on digital satellite, and may be received by anybody with suitable equipment – a high-definition satellite receiver and a satellite dish.