Digital TV and HDTV Essentials
Being familiar with HDTV basics is the first step in knowing what essentials you will need, to make an informed-buying decision.
You may not be thinking about buying a new TV right now, but at some time in the future, you will.
And that time may be much closer than you realize.
A better understanding of the transition to Digital TV, and knowing these HDTV basics, will help you to be ready when it's time to consider a new television.
Buying a new television today involves more than just a quick trip to your local electronics Super Store. Shopping for a Digital TV or an HDTV can be compared to entering a 'labyrinth' of such complete confusion, even the great 'Houdini' would be challenged to find his way through it.
Consumer Choices
So numerous are the decisions confronting today’s unsuspecting and unprepared consumer, just trying to navigate through this complex maze can be a daunting experience. However, many of these frustrations can be avoided by doing some homework before hand.
What this means for the consumer is - ‘Know … Before You Go’.
KNOW what Digital TV is … and is Not.
KNOW what the Digital TV Transition is … and how it affects you.
KNOW that HDTV is ‘different’ from All other television formats … and How.
KNOW what YOU want – so you’re not Sold something YOU don’t want!
But Where To Start?
That’s where HDTVInfoPort can help...
By providing reliable and useful information, that enables YOU to make informed buying decisions.
And since you're - conveniently - already here, this is the best place to start :>)...
So let's start by taking a look at some of the different options you have;
and a few of the first decisions you will make.
TV Classifications:
NTSC Analog TV– (National Television Systems Committee), Traditional TV; now being phased out.
ATSC Digital TV – (Advanced Television Systems Committee), DTV;
This is “SDTV” - Standard Definition TV – the new, (digital) TV Standard;
replaces NTSC Analog TV.
Integrated HDTV – or simply, HDTV; DTV with an Internal (built-in) High Definition TV Receiver.
This is able to Receive and Display all ATSC TV Signals - Including HDTV Signals.
Digital-HDTV – ‘Capable’ or 'Ready'- Digital TV that is able to DISPLAY HDTV - BUT ONLY with the addition of an EXTERNAL HDTV Receiver.
EDTV – Enhanced Digital TV - a classification* describing Digital TV’s that are basically ‘high-end’ SDTV’s. While these often include some type of technical features, added by the Manufacturer to enhance the picture, nevertheless, the picture quality does NOT equal HDTV. Technically, there is virtually no visual difference between an SDTV and an EDTV – with the possible exception of the higher price.
* For many Consumers, this classification is of questionable value; by paying more for a TV tagged “EDTV” the consumer is only getting what can best be described as an ‘upgraded’ SDTV. The question is, how ‘up-graded’ is it, if the TV simply meets the standard for SDTV?
Different TV Display Types:
Direct-view – Images displayed directly on the picture tube (as in the traditional CRT – Cathode Ray Tube) or one of the new, alternative technologies with a “fixed pixel” screen; ie: LCD (Liquid Crystal Display); Limited Display Size – maximum range, about 40-inches.
Note: Smaller screen sizes, (less than about 34-inches) are less effective for HDTV
RPT - 'Rear Projection TV' – uses multiple, miniature picture tubes, (commonly 3) or pixel display, and a combination of mirrors and lenses to project the image from behind, on to the viewing screen; enables displayed picture to be significantly larger; size ranges: 43 to 70+ inches). Offers best value – picture size and quality at lowest cost.
FPT - 'Front Projection TV' – Projects images forward, to an external screen; more commonly used in Home Theater Systems for displaying DVD Movies; for DTV/HDTV may require purchasing TV components separately – including, TV Receiver, A/V Receiver, Display Screen and Speaker System. Complete Systems can be extremely costly, and may require professional installation. Enables an almost unlimited display size.
Different TV Display Technologies:
CRT - (Cathode Ray Tube):Traditional TV Technology – The established standard for television displays; best overall value – picture quality and cost; major drawback is bulk and mass as size increases.
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Plasma Display - Ultra-thin design, High Contrast Ratings, 'Fixed Pixel' Display: Size up to 60+ inches; some display limitations – costly, high burn-in risk; picture quality affected by inability to display black-color; displays are extremely heavy and fragile; picture quality lost as pixels fade; many Plasma Displays do not display HDTV resolutions. Development continues. |
LCD - Liquid Crystal Display: Thin design, size limitations; good computer monitor; sharp picture for static displays; problems displaying images in motion; many LCD Displays are not HDTV capable. Development continues.
LCoS (Liquid Crystal on Silicon) - Improved LCD Technology, may hold promise for future HDTV display; costly; manufacturing problems continue; development ongoing.
DLP (Digital Light Processor) - Uses Chip and Software Technology - exciting, alternative display technology; excellent HDTV display; eliminates most short comings of other technologies; moderate cost; some viewers question “softer” picture, and use of “color-wheel;” promising future - development continues.
Other – Additional new, alternative TV display technologies are being studied or are in various stages of development.
TV Display Configuration:
Aspect Ratio
The width to height ratio of a TV Monitor or Program.
Aspect Ratio can apply to either the television monitor (hardware), or to the TV program format.
Traditional – (4:3) aspect ratio; the display has 'square' appearance. All Analog TV programs are in 4:3 aspect ratio.
New 'Wide Screen' (16:9) aspect ratio; the display is rectangular.
Digital TV (SDTV) programs can be in either 4:3 or 16:9 aspect ratio.
HDTV is always in 16:9 aspect ratio.
TV Monitors of either aspect ratio can display programming with a different aspect ratio; however, this will affect the way the picture is configured on the screen. We will discuss aspect ratio in greater depth, later on.
All Things New...
As you can see, consumers have a number of decisions to make, long before making their final buying decision.
No doubt, you have also noticed that today’s consumers - especially those of 'us' non-tech's, must contend with a completely, new vocabulary list.
Understanding the basics of HDTV requires us to become familiar with an array of strange-new ‘tech-speak’ terms.
Examples:
Aspect Ratio – width to height (4:3) or (16:9); refers to the TV Display and to TV Programs.
Picture Resolution – 720-p; 1080-i; 480-i/p; – and recently added, 1080-p.
Progressive Scan – display method ("p" in 720-p)
Interlaced Scan – display method ("i" in 1080-i)
D/A - A/D – digital to analog and analog to digital converter
STB – Set-top Box (aka: Receiver, Tuner, Decoder or Descrambler)
OTA – 'over-the-air' or 'off-the-air' - refers to Local TV Broadcasts
(These are just a few examples of the new terminology you will come across. For a more complete list of Digital-HDTV definitions, please refer to the separate section under the heading: Digital-HDTV Glossary)
The Digital TV Enigma
Added to the complexity of Digital-HDTV, and all the confusion generated by the Digital Transition – as if these were not enough - are some perplexing contradictions. It is easy to get entangled in a web of paradoxes.
First – As consumers begin their quest for information about the Digital and HDTV, they soon notice what seems to be an “Information-Void.” Trying to get Useful, and Reliable information about what is needed to buy a digital television set can seem just as difficult, as would attempting to breach security at the highest levels of government.
A visit to the local electronics Super Store is likely to confirm this. Try asking any questions concerning basic HDTV; for example: Does the Transition from Analog TV to Digital TV mean that everyone is forced to buy an HDTV? or, What is the difference between SDTV and HDTV; or What is needed to have High Definition TV reception in your home.
Now compare the different answers you get; or - the lack of any coherent response.
Note: To be fair - there have been some recent improvements regarding available consumer information, compared to just a year ago.
This offers 'guarded hope' that by the time you read this, more accurate and useful information on Digital-HDTV will be readily accessible to consumers.
But counting on this would not be a wise bet.
Second – In stark contrast, at the opposite extreme, is the continuous flow of 'misinformation' and 'disinformation.' This flood of unreliable information has inundated the general public. The path to useful and reliable information is littered with inaccuracies, fallacies and myths. And this is further aggravated by misleading advertising and marketing ploys.
As an example, here’s a question asked repeatedly by perplexed consumers concerning the transition from Analog TV to Digital TV:
"Can you tell me if it's true, that "normal" TV is going to be stopped and everyone will be forced to buy an HDTV? I don't believe they can do this ... But if it's true, when will it happen?"
Okay, that's really two questions…
The answer to the first, is of course - NO, it's not true. At least not in the way the question is posed. While it is true that "normal TV" (meaning traditional NTSC-Analog TV) will end, replaced by ATSC-Digital TV, you will NOT have to buy an HDTV!
IMPORTANT NOTE: The FCC's mandatory transition from Analog TV to Digital TV does NOT refer to, nor mean 'High Definition Television!'
This highlights one of the primary sources of so much of the public's confusion concerning Digital TV and HDTV. These are two discrete terms, yet they are frequently used incorrectly - as if they were interchangeable words with the same meaning. They are NOT the same; they designate two distinctly different classifications of television.|
High Definition Television is 'digital'; however, HDTV is just one (1) of eighteen(18) 'Digital TV Formats' designated in the ATSC Standard.
It is important for consumers to understand that 'Digital TV' does NOT mean HDTV.
Digital television’s "Standard Definition TV" – SDTV - is NOT equal to HDTV - High Definition Television.
In reference to the second part of the above question: "When will this transition be completed?"
The projected cut-off for NTSC-Analog TV is December 31, 2006. However, this date includes the provision – IF (80%) of the public can receive Digital TV signals at the 'STOP' date.
And considering that a number of interim "deadline" dates have been extended, not enforced or simply ignored, it leaves in doubt whether or not the 2006 deadline will be upheld. Thus, the actual "STOP" date for analog TV remains uncertain at this time – (early 2005). The general consensus at present is that the transition to Digital TV Broadcasts will not be completed by the scheduled date.
Unfortunately, you cannot count on obtaining the information you need about digital-HDTV from the average 'Sales Associate' in your local Electronics Store. While you may be fortunate enough to find a sales-person who happens to be knowledgeable about Digital TV, and may even know the difference between DTV, SDTV and HDTV - the odds are not in your favor.
So, it's up to each consumer to inform her/him-self on the basics of Digital-HDTV.
But - Be careful!
Don't take anything for granted; don’t accept statements at face value.
Verify everything you hear or read about Digital-HDTV, comparing it with different sources.
(This includes HDTVInfoPort! While we strive to present reliable information, we don't claim any qualifications or expertise regarding TV Technology. And with the technology constantly changing, information can quickly become outdated.)
Moving Forward by Looking Back ...
Now it’s time to look at how ATSC (Advanced Television Systems Committee) Digital Television (DTV) differs from traditional, NTSC (National Television Systems Committee) Analog TV.
Most of us have never questioned, or even given much thought to the technology hidden behind our TV picture tube. Why would we? After-all, we grew up with TV. It's possibly the most familiar physical object known to every generation since the baby-boomers...
(Well perhaps with the possible exception of today’s “Cell-phone-Camera-Everything-else-Combo!")
As long as our favorite TV programs show up in our living rooms as scheduled, how they get there is of little importance, and even less interest. So, without getting into a lot of "hi-tech-stuff," let's look at the TV set that has been in American living rooms for the past 70-years, or so.
Originally, the standard NTSC Analog TV received the transmitted video signal from a Local Broadcaster. But a major problem with analog signals is that between the transmitter and your TV set many things can interfere, thus distorting the picture displayed on the screen. From a plane flying far overhead, to hilly terrain, tall buildings and even weather and atmospheric conditions, all are obstacles that can interrupt the signal.
Also, the strength of the analog signal is critical. A weaker signal can cause "snowy" and distorted pictures; the weaker the signal the more likely it will be affected by interference - something with which any of us who can remember "pre-cable TV" are only too familiar.
The Digital Difference
Digital TV signals are made up of coded instructions - (the same 'bits' of 'ones and zeros' that make your computer work, and give life to 'CD's' and 'DVD's') - which are transmitted to your Digital Receiver, (aka: Tuner, Decoder or Set-Top-Box "STB") which in turn deciphers the code.
A Digital TV receiver isn't concerned with signal strength, or what conditions exist between your set and the transmitter. As long as the signal gets to the receiver, and the code can be read, the Digital TV is able to reproduce a near-perfect picture - virtually identical to the original, back in the TV Studio.
Ghostly Images... 'Who Ya Gonna Call?'… The 'Digital' Ghost Buster!
A distinct advantage of digital broadcasting is that bad reception is a thing of the past. One reason Cable TV caught on is because it delivers clear TV pictures without regard to the viewer's location. Viewers don't have to be constantly adjusting the antenna in an attempt to "tune-in" a weak signal from a distant transmitter to get a clear picture. Digital TV (DTV) eliminates the "snow" and "ghosting" caused by the weak signals from distant or blocked transmitting towers. If the analog television set does not receive a strong, undistorted signal from the tower, you will not get a perfectly clear picture.
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Both digital and analog television signals weaken, the farther they travel away from the transmitting tower. On an analog TV, the picture slowly deteriorates from bad to worse as the distance between tower and receiver increases. However, the picture on a digital set will stay perfect until the signal becomes too weak for the receiver to distinguish between a (1) and a (0), at which point the image disappears completely.
This has been referred to as "the cliff effect" - the picture remains stable until it abruptly "drops off" the screen. This might be compared to sending Morse Code. As long as the person at the other end can make out the dots and dashes being transmitted they will be able to read the message. Once they lose the distinction between a dot and a dash they lose the message. Digital TV acts the same way; instead of sending dots and dashes, it sends millions of (1's) and (0's) every second.
As long as the TV Receiver can read the (1's and 0's) it displays a virtually perfect picture. The bottom line ... you either receive a 100% quality image, or nothing at all. What this means to the digital television viewer, is not having to worry about getting a "bad" picture. Either you have a picture or you don't. However, if you are receiving over-the-air, "OTA" (Over the Air) broadcasts, it is crucial for the antenna to be accurately directed towards the signal source - the transmitting tower of the station you are watching.
Adding an "H" to 'DTV' = W O W! While our objective is to become familiar with HDTV basics, so far we have focused mainly on Digital TV - DTV. What then is HDTV - High Definition Television? And what is the difference between DTV and HDTV?
We stated that DTV differs from NTSC-analog TV in the technology used to transmit the signal. And we looked at some of the reasons why Digital is better than analog. But when comparing Digital TV or "SDTV" (Standard Definition TV) to HDTV, the difference is as night and day! High Definition Television is digital television – BUT … It's IMPORTANT to understand that Digital TV does NOT mean HDTV! HDTV is just ONE of (18) ATSC designated formats that comprise Digital TV.
| In High Definition Television, the picture displayed on your television screen begins as an HDTV signal captured by HDTV Cameras, (or converted from film or another format with HDTV Equipment). The HDTV Signal is transmitted to the HDTV Receiver and finally displayed on an HDTV-Capable TV Monitor. But it must also meet the ATSC Standards for High Definition Television in order for it to be "true" HDTV. |
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Note: It is more than likely you will confront mis-information stating that Digital TV in various configurations is 'high definition television.' This is NOT True! You may also be told that as long as the TV meets one or two criteria, or if it has been enhanced by the Manufacturer, using some proprietary engineering "magic," this makes it - "as good as" - HDTV. Again, NOT TRUE!
In considering Digital-HDTV, it may be helpful to treat any information you come across, the way that Governments handle relations with Foreign Countries - "Trust ... BUT VERIFY!"
If what you want is HDTV, be sure the television you are considering, is really "True" High Definition Television. How Do you Know a TV is - HDTV? To answer this question a 'bit' of basic TV technology will be helpful.
But hold on; it's okay ... Yes, it's true our stated objective is to provide information for “non-tech's” and leave the ‘heavy’ details to those more technically inclined and qualified. But it will be helpful in understanding some of the basic elements of HDTV by having a firm footing under us. After all, this is a discussion about Digital-HDTV - possibly the most significant 'leap forward' in consumer-technology to impact our society in more than a century! So, just a "wee-bit" of technology - promise!
The image you see on your television screen is comprised of a series of horizontal lines. An electron gun 'shoots' energy beams (light) which strike a layer of phosphor on the inside surface of the picture tube, causing it to glow. These glowing lines create the image displayed on your TV screen. How they are formatted, which resolution is used, what standards are met, are some of the factors that determine the type of television picture you will receive.
TV Resolution.The quality of the picture displayed on the TV screen is primarily the result of the television's "resolution." Put simply, TV 'resolution' refers to how many horizontal lines are displayed on the TV screen.
Note – Although the horizontal lines are counted, (in this instance) this is referred to as the "Vertical resolution," because the lines are counted from top to bottom - or vertically. TV Resolution is sometimes expressed as the total 'pixel' count, which is a product of the number of lines and number of pixels per line; we will cover 'pixels' in more detail later on. Comparison: TV and HDTV Resolution

HDTV resolution compared to other formats
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Interlaced and Progressive
Scan Different TV Display Methods:
Interlaced and Progressive Scan
There are two methods that can be used to display the lines on the screen - either "Interlaced" or "Progressive Scan." The NTSC adopted the standard known as "interlaced" to provide a method of compression that achieves a higher resolution using less-costly circuitry.
The NTSC-analog standard is "525 lines - interlaced, at 30 fps" (frames per second). This may be written as: 525-i/30 fps; however, only 480 lines are used to make the visible image, the remaining lines contain information pertaining to picture synchronization and are not seen. For this reason, the stated 'resolution' usually refers only to the visible lines; ie... 480-i/30 fps.
In using the "Interlaced" method, the 480 lines are created in two fields (phases). The "scan-rate" for these (2) fields is 60hz (60 times per second). In phase #1, the first 1/60th of a second, 240 lines (the odd numbered lines - 1,3,5 etc) are scanned on the tube. In the second 1/60th of a second, (phase #2)- the remaining 240 (even-numbered) lines are scanned. Thus each field of 240 lines is scanned 30 times a second, and produces one complete frame (30) times per second; (1/60 second X 2 fields = 2/60 second = 1 complete frame, 30 times per second). It's the total lines-per-image that indicates the resolution of the system, ie: (525-i or 480-i).
Progressive Scan
Digital TV also has formats that use the interlaced system; however, DTV also uses another system, called "Progressive Scan." The progressive system scans the total number of lines, 60 times a second; not half and half as in interlaced. This means you see the complete image displayed on your TV screen two-times more often. This results in smoother motion; moving images have less ‘motion artifacts’ with none of the visible "flicker." A progressive scan system with 480 lines of resolution is written, "480p." Interlace and Progressive Scan
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As already stated, the ATSC has assigned (18) formats to Digital TV. HDTV is primarily concerned with just two of these formats at present: 1080-i and 720-p. (or Higher! - 1080p HDTV-Resolution is now a reality) The ATSC Standard for High Definition Television accepts either 1080 - interlaced scan lines, or 720 – progressive scan lines, or higher .(Recently – early 2005 – HDTV’s with 1080p resolution have reached the manufacturing phase; but availability is still limited, and prices are extremely high) Digital TV in 480-i or 480-p are classified as "SDTV" (Standard Definition).
SDTV has a sharper, crisper picture than NTSC Analog TV. It is superior to analog simply because the transmitted signal is digital. SDTV can be either (480i) or (480p) but is more often 480p. On smaller (direct-view) TV sets, 480p is noticeably better than Analog TV’s 480i; but on the much larger, "projection" sets, SDTV can not compete with High Definition Television's 720p and 1080i formats.
Note: 1080i displays more lines and thus delivers more information. This produces better "spatial resolution" - producing sharper pictures when the image is "still" or has little motion. Manufacturers have generally preferred the Interlaced format because more lines of resolution can be delivered with less bandwidth, resulting in lower costs.
Many viewers, including those in the computer world, prefer the 720p format because its full frame, progressive scanning, enables it to reproduce fast-moving action and graphics without blurring the image. This is the reason that 720p is said to have better "temporal" resolution.
Incidentally, if you have a computer system - doesn't everyone? - your monitor uses progressive scan. Both sides in this (i/p) debate are dug-in, with ardent supporters and aggressive detractors abounding on each side. But which is the better system is a subjective determination. You might say "it's in the eye of the beholder." However, the introduction of 1080p should bring this debate to an end.
The different television networks have individually selected the particular DTV format used by their respective networks for transmitting High Definition Television broadcasts. For instance, ABC and the FOX Network chose to use 720p; while CBS and NBC transmit in 1080i. The important note for consumers concerning HDTV resolution, is that the TV is capable of converting incoming signals to whatever the set’s native resolution is; this allows viewing all TV signals in the set's designated (native) format. Pixels - Picture Elements High Definition Television displays pictures that contain significantly more detail, resulting in much 'crisper' pictures.
Images viewed on TV screens are made up of small picture elements known as 'pixels.' Each of these pixels is made up of three, closely spaced 'dots' of color - red, blue and green. Combined together on the TV's phosphor screen, and viewed from a distance, the colors are seen as one. The phosphor at each of these dots emits light directly proportional to the intensity from the electron beam that hits it, as it scans across the screen.
On traditional - NTSC - TV's, 256 levels of intensity are possible for each of the three colors. The result is a range of 16.8 million colors for each pixel. The pixels in the analog system are slightly 'taller' than their width. Get up close to an analog screen - especially the larger projection sets - and you can easily see the red, blue and green rectangles. This is why distortion is sometimes seen on traditional, NTSC TV's. The pixels in HDTV sets are square; they are also smaller, and spaced closer together. There can be (4 1/2) HDTV pixels in the same space that a single NTSC pixel requires. The result is that High Definition Television can display at least 4.5 times more detail than NTSC-analog TV.
More About "Aspect Ratio"...
Why Is "Wide-Screen" TV The DTV Standard?
DTV sets are sold in two 'Aspect Ratios.' Aspect Ratio refers to the ratio between the horizontal (width) measurement and the vertical (height) measurement of the screen. This ratio is also used in reference to how the picture is transmitted and displayed on the screen. The two aspect ratios used in DTV are (4:3) and (16:9). That is, (4) units wide by (3) units high, and (16) units wide by (9) units high respectively. Your NTSC-analog television has an aspect ratio of (4:3); the screen appears almost 'square' because it has just slightly more width than height. For instance, a (4') wide screen would have a height of (3').
Digital Television's (16:9) 'wide-screen' is approximately (1/3) larger than a comparable (4:3) TV screen. As a comparison - if you have a "wide-screen' set measuring (16) units wide by (9) units high, then a comparable (4:3) set would measure (12) units wide by (9) units high.
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The ATSC adopted the 16:9 "wide-screen" aspect ratio as the standard for Digital-HDTV, because significantly more information can be displayed on the screen. And Wide-screen DTV/HDTV sets appear more 'rectangular' than the familiar 'square' shape of your NTSC-analog set. (Don't confuse this with screen "size," which is the screen's diagonal measurement) |
Wide Screen Display.. Better - Why?
How the aspect ratio evolved…
It may be of interest to note that the traditional 4:3 aspect ratio was originally developed back in 1889, by W. K. L. Dickson, while working at the famed Thomas Edison Laboratory. At the time, he was running experiments with a Kinescope (early motion-picture) camera. Dickson arbitrarily decided to create his film (1") wide and (3/4") high. And this ratio, later became the standard of the film industry. In 1941, when the NTSC proposed the standards for broadcast television they had no reason not to adopt the same 4:3 ratio used by the film industry. And it was a later benefit as TV producers began telecasting movies filmed in the format.
In the 1950's, Hollywood found they needed to provide the public with a specific reason to buy movie tickets, since people found it preferable to sit home and enjoy free television, rather than pay to see a movie. In addition to trying innovations like "3-D" movies, the studios experimented with aspect ratio; "Cinemascope" was one of the early 'wide-screen' ratios that can still be seen today. The reasoning that led to wide-screen formats is simply that the wider view is closer to the human field of vision. And because the viewer is visually drawn into the action more with wide-screen, the enjoyment level is enhanced.
Our vision is optimized within a 30-degree field of vision. We see details best within the 'center' area of this field, while our peripheral vision is better at detecting motion. Beyond 30-degrees there is no visible benefit. The familiar 4:3 ratio allows us only a 10-degree field of vision. In the theater, 'wide-screen' formats were easy to reproduce by using more or less of the area projected on the screen, as needed. However, as movies were displayed on TV screens, and later made into videos, the aspect ratio became more complicated.
Initially, movies were 'cropped' to 'fit' 4:3 analog-TV sets. This is accomplished by a process called "pan and scan," which involves moving the 4:3 viewing area back and forth, to center the scene on the primary action. While pan and scan is okay if nothing is occurring in the peripheral areas, often, important information in these areas is cut off. In addition, pan and scan may not give the viewer the same "feel" that the original film had, because the scene is not actually seen as the movie director intended.
To enable movies to be viewed in their original, 'wide-screen' aspect, the letter-box process was developed. With letter-boxing, the picture's height is reduced, thus allowing the full width of the image to fit the TV screen. This enables you to see the entire scene the way it was filmed. However, reducing the image height requires removing some information that leaves a portion of the vertical area 'blank'; this appears as a black 'bar' on the screen. The image is displayed in the center of the screen, with the blank area divided into two, horizontal, black 'bars' across the top and bottom of the screen. These bars increase or decrease, as the aspect ratio changes.
However, 'letter-boxed' movies, originally filmed in extra-wide format, can be especially troublesome when viewed on smaller TV screens, due to the extremely reduced viewing area.
Letter-box and Window-box. It's important to understand that the digital signal can be transmitted in either the (4:3) or (16:9) aspect ratio. It's anticipated that all DTV will be broadcast in (16:9) at some future date. However, today’s Digital TV’s are able to display both transmitted aspect ratios, regardless of the ‘native’ ratio of the TV set.
Important Note: When you watch a program that is transmitted in (4:3) aspect ratio, on a (16:9) screen, the image will be "window-boxed" - centered on the screen with vertical black bars (gray on some models) on both sides of the picture. When you watch a (16:9) program on a (4:3) screen, the picture will appear letter-boxed (previously described) with horizontal bars across the top and bottom of the screen.
This brief introduction to Digital TV and HDTV basics, provides an overview (intentionally simplified) of how DTV differs from traditional Analog TV, and how HDTV differs from Digital-SDTV; and a little about the Transition from Analog TV to Digital TV. This is just a start towards a better understanding of Digital TV. Now that you're familiar with some of the basics, you are better prepared to begin considering which Digital HDTV is right for you. The HDTV-Buyers Guide* will show you the way to proceed - when you're ready.
The adventure into the exciting, new dimension of HDTV has begun… The High Definition Television Experience awaits you.
. . . and it IS worth it!
*Use the Navigational Links (Below - or in Top-Left Column of this page) to go to the HDTV Buyers Guide - details items to consider, before buying your new, Digital-HDTV) Use the Search Function (below)... Type the key-word(s) related to specific information you are looking for, in the box below, to access additional information and resources ...
| Important News For Consumers ...
(HDTVInfoPort Report: 05-12-2006)
Among the most frequently asked questions we get from Consumers are:
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"What is the "best" Digital-HDTV ... ?"
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"How do I decide which HDTV is "right" for my family?"
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"With so many decisions to make, I'm totally confused ... how can I possibly 'know' - what is the "best" choice?"
Why not try - "Choose It!"© - An ingeniously simple, new tool that empowers consumers in decision-making. Find out how you can choose the "right" HDTV (for you) ... shhh .. It's "free!"
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