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Standard-Definition Versus High-Definition

Differences between Standard & High-Definition Televisions

Standard-definition televisions (SDTVs), like the bulky old CRTs for example, are able to display up to 480 or 576 lines of interlaced video depending on the source. An interlaced scan consists of two fields, made up of odd and even lines. For instance, an SDTV scans a PAL signal (a video signal standard in this region) at 25 frames per second - with each frame consisting of odd and even fields, resulting in 50 fields per second. Many terrestrial programs are broadcast in such SDTV formats, like Channel 5 and 8 from MediaCorp. However, interlaced displays are prone to flickering or "shimmering" issues due to the alternating fields.

Modern digital TVs, on the other hand, would convert the interlaced signal (a process called de-interlacing) to a smoother progressive format. A progressive scan has the lines "painted" in one at a time in sequential order, instead of alternating between odd and even lines. As such, we've 50 frames per second, instead of 25. In layman's parlance, progressive scans refresh the image in "full", while interlaced ones have frames which alternate between two fields. As a result, a progressive scan is able to give you a sharper and smoother image, especially noticeable in sports and fast-action movies.

Also, high-definition televisions (HDTVs) can display resolutions of up to 1080 lines, compared to an SDTV's limitation of 576 lines. Furthermore, most HD tellies also feature the 16:9 widescreen aspect, instead of the boxy, traditional 4:3. In fact, HDTVs only come in 16:9 widescreen format, whereas SDTVs can come in either the 4:3 or 16:9. Also, note that HDTVs are fixed displays. Depending on the picture, a HDTV would either scale up or scale down the image size to suit its native resolution.

 

What Do the Stickers Signify?

Generally, there are two primary types of HDTV panels available for retail in the local consumer market: HD-Ready and Full-HD. The two descriptions might sound similar but they're actually quite different in terms of picture resolution. Acquaint yourself with them here: 

HD-Ready: Most HD-Ready screens are able to display 720p and 1080i HD sources, and possibly 1080p. Characteristically, a HD-Ready TV features a fixed resolution of 720 lines x 1280 pixels which is lower than the Full-HD range. TV specs would commonly use the "720p" nomenclature. As mentioned above, HDTVs are limited by their native resolutions regardless of the picture source.

Translating that, even a 1080i picture remains effectively at 720p on such displays, since HDTVs are unable to vary the number of physical pixels they carry. "HD-Ready" descriptions are generally found on TVs with smaller screen sizes. However, Full HD displays are also fast becoming the standard with recent HDTV models of smaller size. Generally, HD-Ready screens are adequate for TVs of 32-inches or smaller as they don't benefit from higher resolutions with a small display area.
 

Full HD: If a TV carries the Full HD sticker, you can be assured of a larger display resolution - 1080 lines x 1920 pixels. It is commonly denoted by the "1080p" nomenclature in specs. Obviously, this makes it more attractive than the HD-Ready breed. With Full HD screens, the pixels are more tightly packed which enables the viewer to sit closer to the display as well. Best of all, no scaling is involved when the TV is receiving 1080i or 1080p inputs.

With over-the-air transmissions, a handful of premium Full HD models come with integrated digital tuners which removes the need for a HD set-top box. There's more on the digital tuner in the following section. As a general note, Full HD screens are only beneficial if your screen is 40-inches or larger to really enjoy the difference between 720p and 1080p resolution based content.

 

High-Definition Content - How to Get Them

There are various ways to tap into HD sources. However, not all of them are necessarily legitimate. Apart from the various outlets mentioned below (which are perfectly legal by the way, provided you pay your bills), some of the more recent and premium television sets also come with widgets which allows you to view HD streams online, such as YouTube. Many such TVs are currently termed as Smart TVs.

Terrestrial & Cable HD: By 'terrestrial', we're referring to free-to-air analog TV transmissions. With digital terrestrial HD broadcasts, however, it's best to get a TV with a built-in digital (DVB-T) tuner plus an integrated MPEG-4 AVC decoder function. A digital TV antenna is required as well. There are other workarounds, such as obtaining a DVB-T set-top box if your TV lacks the tuner.

If you've a cable subscription, you'll need to grab a HD set-top box from the cable company to decode the DVB-C signals. Over the terrestrial route, MediaCorp is currently offering a number of digital SD channels such as Channel 5, 8 and CNA, with HD5 being the only channel offered in the 1080i HD format. For cable users, StarHub has 14 dedicated HD channels at present, including popular selections such as History HD and Discovery HD. Alternatively, there are IPTV HD channels available as offered by SingTel's mio TV. By the way, most HD broadcasts are transmitted either in 720p or 1080i. Full HD 1080p transmission consumes too much bandwidth for now, plus 720p/1080i is compatible with a wider variety of old TVs.

Blu-ray Disc: Blu-ray playback is by far the most common solution in obtaining an HD fix. However, Blu-ray films are inevitably more expensive than standard-definition DVDs given their higher fidelity and storage. A Blu-ray disc (BD) is capable of holding up to 25 GB of data on a single layer, and it's also able to store 2D as well as 3D video content in Full-HD formats.

While BD titles still command a relatively steep price tag, Blu-ray players, on the other hand, have witnessed a sharp decline in prices. It's possible to snag an entry-level player for S$150 or less. Indeed, avid gamers can alternatively pocket two birds with one stone with the Sony PlayStation 3, since the gaming console effectively doubles up as a Blu-ray player. Recent players fitted with the BD-Live profile also come with Internet capabilities.