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HDTV

Japan had pioneered HDTV for decades with an analogue implementation. However, both it and a similar attempt in Europe ultimately failed. Japan again took the lead in digital HDTV, this time along with the USA, who began digital HDTV transmissions as early as 1999, as part of a broader introduction of digital television (DTV). In the USA it was originally expected that sporting events, movies, and primetime programming would likely be shown in HDTV, while daytime programming, news and the like would probably be shown in SDTV. Given the high cost, the slow take-up was understandable and by the start of the new millennium only a few thousand receivers had been sold.

HDTV’s introduction in the USA stumbled somewhat, but was boosted by Fox Sports’ HDTV transmission of the 2005 Superbowl. In Australia, uptake was also sluggish initially, but has increased significantly since 2003. Belgian broadcaster Euro1080 launched the first commercial satellite broadcasts of HDTV in Europe at the start of 2004, but other broadcasters were slow to follow.

By the beginning of 2006, HDTV services existed in Japan, USA, Canada, Australia and South Korea. Japan was the TV technology leader, but the global HD market was focused on America, where more than 40 HD channels were on offer. HDTV transmissions were set to take off in Europe by the time of the football World Cup being staged in Germany that summer, with UK satellite broadcaster Sky amongst those planning to have launched services in good time for the event. The BBC (the UK public service broadcaster) has said that it intends to produce all of its content in HD by 2010, but not disclosed when it plans to begin transmitting HD content. Market research suggested that more than 4.5 million households in Europe would switch on to HDTV by 2008.

Unlike in Europe, in the USA HDTV was integral to the introduction of DTV. For several years the computer and TV industries lobbied for their favoured formats. The former wanted a scalable, frame-based format. The latter called for a format that was interlaced, with each frame drawn up in two passes, or fields, of odd then even lines. The original compromise was a confusing mix of different formats – 6 HD and 12 SD formats – each with a different aspect ratio, resolution and scan mode.

HDTV encompasses six video formats, including the 1080-line interlaced (1080i) format at either 24, 30 or 60 pictures per second, and the 720-line progressive (720p) format at the same picture rates. All these formats will have a wide-screen, 16:9, aspect ratio. The formats using 24 frames per second are designed to allow excellent reproduction of motion picture (movie studio) content, which would otherwise suffer timing artefacts from being converted to 30 or 60 frames per second. HDTV receivers must support them all and it’s been left to the broadcaster which to transmit.

The table below summarises the characteristics of the principal DTV standards:

Active Lines

Per Picture

 Pixels

Per Line

 Aspect Ratio Frame Rate Scanning
HDTV 1080 1920 16:9 24, 30, 60 Progressive
1080 1920 16:9 24, 30, 60 Interlaced
720 1280 16:9 24, 30, 60 Progressive
SDTV 720 704 16:9 24, 30, 60 Interlaced
480 640 4:3, 16:9 24, 30, 60 Progressive
480 640 4:3 24, 30, 60 Interlaced

The fact that the standard adopted by the FCC includes 18 separate resolution and display formats, may have created a deal of confusion for the broadcasters, but at least the industry can take comfort in the prospect that one of the formats, 24p, offers unique advantages to the post-production community.

 

Filed Under: Digital Video

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