Thursday, September 25, 2008
10 Mitos de HDTV (Televisión Digital de Alta Resolución)
Top 10 HDTV Myths
Fact vs. Fiction, Hi-Def Style
By Popular Mechanics
Photo: Chris Eckert / Studio D
High-definition television (HDTV) has evolved from an early-adopter indulgence to a mainstream technology in less than a decade. Enthusiasm for HD everything is driving the sales of flat-panel TVs and has inspired a next-gen DVD format war. It's showing up in camcorders and on your local TV news.
Yet HDTV remains a widely misunderstood technology, muddled with misconceptions and half-truths born of marketing mumbo jumbo and senseless jargon. The advertised specifications read like bewildering mathematical equations with "variables" such as 1080i, 720p, 4:3, 1080p and 16:9. To clear the air of confusion we've examined some of the most wrongheaded bits of received wisdom in the world of HD.
More from PopularMechanics.com
Everything You Need to Know About the Digital TV Transition
7 Steps to Buying a New LCD TV on Your Budget
How 3D on the Big Screen Will Change Tech in Your Living Room
You need a cable or satellite TV subscription to watch HDTV programs.
Fact: If you live in or near a city, it's likely there are several over-the-air local TV stations broadcasting HDTV programs, which you can watch for free. ABC, Fox, NBC, CBS, PBS, and CW networks all offer HDTV programming (local HD listings are available at antennaweb.org). You can receive them with the tuner in your HDTV set or an external DTV set-top receiver, but you need an external HD antenna.
You can buy a flat-panel HDTV with 1080i resolution.
Fact: Much of the confusion on this one comes from the difference between broadcast formats and display resolution. Some networks broadcast using a 1080-line "interlaced" (refresh every other line every other frame) signal, while others broadcast a 720-line "progressive" (refresh every line every frame) signal. But all flat-panel TVs display video progressively, regardless of the source signal. The way to assess the resolution of a plasma or LCD set is to check its total pixel count (e.g., 1280 x 768, 1920 x 1080, etc.).
HD video can't be recorded to regular DVDs.
Fact: Yes it can. New blue-laser discs such as Blu-ray and HD-DVD have high capacities, up to 50GB, but conventional red-laser DVDs can hold hi-def, too. Recording capacity is about 30 minutes for an HD program with the MPEG-2 digital compression system in widespread use today. But efficient codecs such as MPEG-4 and Windows Media can fit entire HD movies onto conventional DVDs that play back on computers and some DVD players.
A 1080p TV is always better than a 720p TV.
Fact: A 1080p set (one with at least 1920 x 1080 pixels) does have higher resolution than a 720p (at least 1920 x 780) set. But the importance of those extra pixels depends on the size of your TV and the distance you are away from it. If you are sitting more than 8 ft. from a 42-in. HDTV or more than 10 ft. from a 50-in. set, you won't notice the difference. If you mostly watch standard-def TV and DVDs, an expensive 1080p set makes no sense — a 720p set will work fine.
An HDTV set automatically converts all programs it receives to HDTV.
Fact: HDTVs can stretch a standard definition (SDTV) image to fit their screens, but they can't magically add resolution. Since SDTV has only 640 x 480 pixels, hi-def TVs tend to magnify the fuzziness of standard-def video — sometimes making it look worse than it would on a non-HDTV set.
All flat-panel televisions are high-definition.
Fact: To make sure you get HD resolution, you need to do pixel math. Many 42-inch plasma TVs are sold with 1024 x 768 pixels. But the two high-definition broadcast standards are 1280 x 720 (720p) and 1920 x 1080 (1080i). So 1024 x 768 plasmas give you only 85 percent and 38 percent of the pixels, respectively.
To get the best-quality HD, you need expensive cables.
Fact: Not true. If the cables running from your DVD player or cable box aren't particularly long, you should be fine with inexpensive video cables. The extra shielding in expensive cables that prevents interference in analog equipment won't improve the image of digital video through HDMI or DVI cables — the signal either comes through or it doesn't. And the savings can be huge: 6-ft. HDMI cables range from $20 to $160.
HDTV means consistent picture quality.
Fact: Definitely not true. To transmit HDTV programs, cable system operators, satellite companies and over-the-air broadcasters compress their signals. And some shows are compressed more than others. To fit more programming into existing bandwidth, broadcasters often take a channel designed for one HD program and squeeze multiple SDTV and HDTV programs into it. That can lead to squirmy backgrounds and other compression "artifacts." Unfortunately, there's not much that average viewers can do about this — except to complain to their cable or satellite providers.
All 1080p HDTVs accept 1080p input signals.
Fact: There are a few "1080p" HDTVs out there that have 1920 x 1080 pixels and can display 1080i television signals, but can't accept an external 1080p signal from a scaling DVD player or HD-DVD and Blu-ray players. Always check the manufacturer's specifications for signal compatibility.
Blu-ray and HD-DVD discs always offer the highest possible resolution.
Fact: That depends on how the discs were mastered from the original movie. Some discs are transferred from an early-generation digital copy, while others are scanned from a later-generation film print of poorer quality. There's no labeling on the Blu-ray or HD-DVD packaging to give customers a quantitative measure of relative video quality, but it's worth scanning reviews on enthusiast Web sites such as highdefdigest.com.
Reprinted with permission from Hearst Communications, Inc.