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FEATURE
HDTV Heaven
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On the world stage, HDTV has been around for a while, particularly in the US and Japan. Australia has seen a painful process, where broadcasters have been mandated to provide a minimum quota of high definition broadcasts. Worse still, there’s a great deal of variation between the broadcasters, with some simply upconverted standard definition video to high definition resolutions, while others broadcasting true, native 1080i HD signals.
This chaotic situation of slow uptake and varied signal types has arisen largely from the painful costs in moving to HD broadcasting, which affects everyone in the distribution chain.
It starts with production. While standard definition (SD) programmes can be ‘upconverted’ to run in HD, the result is like using the digital zoom on a digital camera or resizing an image in Photoshop; the new pixels have to be interpolated from existing ones, so you don’t actually get any more detail. True HD programmes are shot using HD cameras, and produced using HD editing and processing equipment. Even for a small production company this is a sizable investment. Even the mighty BBC has had some trouble – it has already filmed flagship programmes in HD, including Planet Earth, Bleak House and the second season of Doctor Who, but it will be some time before HD becomes the norm across its output.
And for a broadcaster, that isn’t the only expense. Whatever the transmission platform – cable, satellite or terrestrial TV – broadcasters have a finite quantity of bandwidth to play with. This means HDTV signals need to be compressed, and as a single uncompressed MPEG2 channel might take up to 885Mb/s of bandwidth at 720p, they need to be compressed efficiently. The widespread industry adoption of the MPEG4 AVC format (also known as H.264) has dragged down the requirements to a more practical 5 to 8Mb/s, but also demanded another heavy investment in equipment. In short, HDTV puts more pressure on the broadcaster, and more pressure on its broadcast infrastructure.
And finally, there’s the cost to you: first, in terms of HD LCDs, televisions or receivers, and second, in sorting through the mess of deciding what, exactly, constitutes a HD product. The latter refers to the complicated web that various vendors have weaved to market their wares as HD compatible. A ‘HD-ready’ monitor or TV can be described as HD-capable, HDTV-compatible or HD-ready. It’s here that you need to be wary. If a manufacturer describes a screen as HD-capable, it simply means that the device is physically capable of taking data from a high-definition source and displaying it at the appropriate resolution. This doesn’t, however, mean that it has all the necessary inputs and technology to do so, and we’ll cover the reasons why this is vital later.
To get around this, an official certification process is vital, and unfortunately lacking in Australia. This would indicate to consumers whether the screen they’re purchasing will receive a native HD signal and display at its intended resolution. Ideally, it would be similar to the European industry body, EICTA, which has recently launched two logos, HDTV and HD-ready. The latter means that the product satisfies the minimum requirements for HD display: a 720-line display in the widescreen aspect ratio, support for 576p/720p and 1080i sources, an analog component-video input and a digital DVI or HDMI input, plus support over the digital input for the HDCP (High-bandwidth Digital Content Protection) protocol.
In addition, any reception equipment, including integrated sets with integrated HDTV receivers and set-top boxes, should show the HDTV logo. This ensures that it supports the necessary file formats (MPEG2 and MPEG4 AVC) at the necessary resolutions (720p and 1080i) with the necessary outputs (component video, DVI or HDMI), and with the necessary content-protection protocol (HDCP). This should, theoretically, guarantee that HDTV will work on your equipment.
Oddly, it’s the HDCP support that proves critical. HDCP is a standard encryption/decryption copy protection protocol designed to reassure the Hollywood studios and their TV equivalents that content won’t easily be copied directly from a digital output. The important thing to understand is that HDCP has to be supported all the way through the device chain, every time one piece of equipment connects to another. Your HD DVD or Blu-ray player will need to support it, as will your TV and your HDTV receiver. If not, any HDCP-protected content will turn up as a blank screen or as a working image with the resolution downgraded to SD.
In most cases, this won’t be a problem. If your HDTV-compliant receiver is connected to the HDMI connection or HDCP-compliant DVI input on your HD-ready set, everything works. The problem is that there are so-called HD-capable screens out there that use either an analogue component video input or a DVI input without HDCP support. As the HD DVD format looks set to demand HDCP compliance (the Blu-ray format does not) and much US-generated content will be HDCP encoded, this may cause much grief to those who invested in non-HDMI TVs in the past few years. And, as we’ll see in a minute, it also causes problems for anyone planning to enjoy HDTV on their PC.
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| Sports are destined to be a major HDTV showcase. |
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| The BBC's Planet Earth was shot entirely in HD, even though its initial UK broadcast is in standard definition. As HDTV grows in Australia, the US and Japan, JD will be a must-have for programmes destined for international sales. |
This article appeared in the July, 2006 issue of PC Authority.
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