Fact or fiction? 8 HDTV myths demystified
- — 09 March, 2010 03:06
If you're buying your first HDTV or an upgrade from a starter set, your new television may deliver a better picture than the one you're used to. But picking the right HDTV can be confusing, especially when your favorite blue-shirted salesperson may be steering you in a certain direction in hopes of a bigger commission. Or maybe the rep is just misinformed. Whatever the reasons, the environment has rncouraged a cavalcade of claims about HDTVs--some of which were true for first-generation sets but have little relevance to today's buyers, some of remain valid, and some of which were never true.
I'll highlight some of the most prominent assertions made on the showroom floors of big-box retailers and explain the realities, along with tips and details for buying an HDTV, selecting the best content, hooking up the set at home, and more.
Claim: "HD" signifies a specific standard of quality.
Though "HD" does stand for "high definition," HDTVs come in several resolutions; and in any event, a set's resolution doesn't completely determine the exact image quality you'll see on your screen. For one thing, screen sizes vary. Other factors affecting the picture include the transmission--over the air, via cable, by satellite, or from the Internet--and the original source material.
These variables help explain why you can get high-def content from Amazon, Hulu, iTunes, Netflix streaming, a Blu-ray disc, and other sources, and yet encounter wildly different picture quality.
The basis for the real broadcast signal standards is ATSC (Advanced Television Systems Committee), and even that has many options.
If you have an HDTV and a digital tuner, ATSC governs your over-the-air signal. ATSC content may be in either standard-definition (in either 4:3 or 16:9 aspect ratio) or high-definition (16:9 aspect ratio) format, with the resolution varying accordingly. A standard-def transmission consists of 4:3 images transmitted at a resolution of 640 by 480 pixels.
The most familiar of the HD resolutions are 720p (consisting of a 1280-by-720-pixel frame) and 1080i (composed of 1920-by-1080-pixel images). The "p" stands for "progressive scan," meaning that the set creates the image by continuously redrawing the frame, line by line. The "i" stands for "interlaced," meaning that halves of the full frame are shown 60 times per second, but your eyes combine them into a full-frame image reproducing itself at a rate of 30 frames per second. At the same resolution, a progressive-format image looks better than an interlaced image.
Over-the-air broadcast standards top out at 720p and 1080i, but you can obtain the full 1920-by-1080-pixel frame in 1080p from Blu-ray discs, certain Xbox 360 models, and the PlayStation 3 units.
Compression and bit rate are other factors in picture quality. A Blu-ray disc should look better than a cable TV feed of the same content at the same resolution, since the disc has more bandwidth than the cable broadcast.
When choosing for picture quality, remember: 1080p is at the top, 720p and 1080i look similar, and anything below them won't be as good. Keep those terms in mind because they represent official standards, not marketing terms.
Claim: If you don't buy a 1080p HDTV, you're wasting your money.
In all likelihood, you want a 1080p HDTV--and you should be sure to get that resolution if your set has a diagonal screen size of 32 inches or greater, since you'll be able to see the additional resolution on a big-screen from across the room. Furthermore, there's no reason to avoid a 1080p HDTV if it doesn't cost substantially more than sets with alternative resolutions, given that 1080p is becoming ubiquitous. If the difference is within $100, I recommend going for a 1080p set if your budget can handle it.
But having said all that, I should warn you that you probably won't see any improvement in picture quality from 1080p versus 720p on a smaller HDTV. And you may not even have any 1080p sources to exploit: Over-the-air broadcasts and most cable feeds top out at 1080i.
If you're getting a big set or if you're connecting 1080p sources such as a Blu-ray player, a Microsoft Xbox 360, or a Sony PlayStation 3, a 1080p set is your best bet. But in many other situations, a 720p set will perform just as well for all practical purposes.
Claim: You bought an HDTV, so everything you view will be in HD.
Today, not everything on television is broadcast in high definition. DVDs and shows that were recorded for broadcast under the prior analog standard will continue to look about the same as before. (Some HDTV sets even make old shows look worse, by showing off more imperfections of the original recording.)
For satellite or cable TV service, you may need to ask your provider to activate HD content. The transition might require setup on both the provider's end and your end; some cable boxes need to be reconfigured to output HD signals even after you connect them with the proper cables.
A 500-station cable lineup may carry both the high-def and standard-def versions of many channels, so make sure that you've selected the HD version of the one you're watching.
Nearly all prime-time broadcast channels and many daytime shows present their content in high definition. If you don't see a night-and-day difference between a prime-time broadcast in HD and what you remember from analog TV, something isn't configured properly. (Check to confirm that the cable box and service provider are sending an HD signal and that you are using HD-capable cables.)
An Xbox 360, a PS3, a cable box, TiVo, and nearly any other HD-capable device can output in either high definition or standard definition. After you connect an HD-capable cable, you'll probably need to update a settings screen to tell the device what resolution of signal to output. Here's how to get started with a few common devices.
On the Xbox 360, if you're using the component connection, be sure to flip the switch on the cable to HDTV. Go to My Xbox, System Settings, Console Settings, Display, and choose HDTV Settings. Select the option that matches your TV's highest resolution.
On the PlayStation 3, choose Settings, Display Settings, Video Output Settings. Select the cable type connected to your TV, and choose the resolutions that your TV can display.
On the TiVo HD, select TiVo, Messages and Settings, Settings, Video, Video Output Format. Since broadcasters may present different TV shows at different standards, you can instruct your TiVo to keep their native settings or to scale them for your TV. Review the options here; I like to keep the Native setting.
Claim: DRM can prevent content from playing on your HDTV.
Digital rights management (DRM) tools prevent you from copying copyrighted content. In most cases, HDCP--High-bandwidth Digital Content Protection--is the benevolent cop. HDCP is a handshaking protocol that provides a foundation for DRM. (The actual DRM can vary or be hidden, so look for HDCP labeling.) To avoid any problems, though, you need to use the correct gear.
HDCP works with Blu-ray discs, digital downloads, and other content sources. The technology checks for an unbroken digital connection from your content source to your TV. If the digital connection breaks off--perhaps because you connected to an unauthorized splitter or are using an analog feed--HDCP will detect that fact. In such situations, using DRM enforcement, HDCP can throttle your show quality or stop you from watching at all.
To ensure--or to be as sure as possible--that DRM won't prevent you from watching shows, connect an HDMI or DVI cable between your source and your TV or monitor. (If you use HDMI, then by default you have an HDCP-protected connection, and you're good to go. But if you try to use a monitor or an older HDTV with DVI as a display device for protected content, verify in their manuals that both devices support HDCP.) If you need to connect to a splitter, receiver, or other device in the middle, make sure that it supports HDCP, too.
Claim: Brand-name cables are worth the extra money.
Don't buy cables strictly on the basis of their brand name. A cable's connector type, length, and gauge are the most important factors in signal quality. As a first criterion, choose a digital cable if possible--either HDMI or DVI (just about any new HDTV will include a digital connection). Such cables can carry a 1080p signal if your content supports it, they'll play nicely with DRM, and they won't pick up interference the way an analog cable can.
If you don't have a digital connection, you can still obtain signals at up to 1080p via component cables. The resulting picture quality should still be first-rate. However, if you drop down to a lesser cable type--S-video or a single, composite RCA cable--say goodbye to your HD signal. At a minimum,your HD-compatible devices should have component, HDMI, or DVI ports. In addition, they probably have S-video and composite ports for compatibility with older televisions. Avoid those ports.
In any situation, get the shortest cables that can make the connection you need. Extra loops of cabling may pick up interference and distort analog signals, and image quality may degrade as cable length increases, especially if the cabling runs across entire rooms.
Thicker cables can improve quality, but the difference is greatest in speaker wire. Consider buying thicker-gauge cabling if you plan to run it across a distance of 50 feet or more.
If you take these steps, instead of reaching for a brand name, you'll get great video and audio connections for a reasonable price. You can save even more on cables at a site such as Monoprice, where you can expect to pay a few dollars for nearly any cable type, rather than $20 to $50 for a single, brand-name HDMI cable.
Claim: You're in imminent danger of burn-in from letterboxing and on-screen graphics.
Burn-in is no longer a serious issue for HDTVs. Years ago, static on-screen graphics from network TV logos, stock tickers, videogames, letterbox bars, and other patterns could wear unevenly on a TV. If you left your set on and tuned to a station that showed such stationary elements for hours at a time, you might have been able to see them lingering when you tried to watch other content. First-generation plasma screens were the ones most susceptible to this effect.
LCDs and other TV types haven't exhibited this issue, and recent plasmas have incorporated effective countermeasures against the problem. If you're buying a new set, don't worry about burn-in.
Plasma TV watchers may encounter temporary image retention--which can look the same as permanent burn-in--but the images eventually go away. Static images imprint themselves in a way reminiscent of permanent burn-in. But in this case, the pattern fades away with normal use. To speed up the process, play a station with a static pattern, use a PC utility such as JScreenFix, or activate the TV's built-in mode to clear the problem.
Claim: HDTVs can cause audio-sync problems with games.
Music videogames such as Rock Band and Guitar Hero require perfect timing between audio cues and on-screen graphics. If the two are not aligned, the most likely cause is that the TV is performing extra image processing but audio is being routed directly to a receiver. As a result, the picture gets slowed down, and the audio plays too soon.
The tiny delay that some TVs add may be perceptible only in these games, but you can turn off extra video processing in the TV's menu system. Look for a "game mode" setting. Most recent music games can recalibrate to take the delay into account. Look for those settings in the game's options.
Alternatively, you can solve the problem through the audio; receivers often give users the option of adding their own compensatory delay. If your HDTV set feels a little slow when you use it for gaming, read about how to reduce your input lag.
Claim: A TV with a faster refresh rate can look better than a slower TV.
In the past few years, vendors have marketed TVs with refresh rates of 120Hz, 240Hz, and beyond. These sets can interpolate frames between the ones you'd normally see, thereby smoothing out motion through enhanced picture processing.
PCWorld's HDTV testing has demonstrated a correlation between high refresh rates and smoother image quality in TVs. However, we occasionally see high-refresh-rate TVs whose images look more jittery than those on 60Hz sets. These discrepancies arise because smooth motion performance depends on the combined operation of the panel's refresh rate and the software algorithms inside the set.
As 3D-capable TVs come to market, refresh rate will play an increasingly important role in picture quality. One technique used to produce 3D effects requires input and playback of a 120Hz signal. (Practically all current TVs accept only a 60Hz signal, regardless of their advertised refresh rate.) Look for 3D branding and a 120Hz input in those cases.
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