Digital TV
Resolution Standards
Based on vertical scan rates, digital TV has much more capacity for a finer
detailed image than that of analog TV. However, In order to display the raw scan
lines, a video monitor has to be able to reproduce the full detail of the
incoming DTV or HDTV program material. In addition, true HDTV is also dependent
on a monitor that displays the image in a 16x9 screen shape. However, there are
also HDTV monitors in the traditional 4x3 shape, in which case a 16x9 image is
displayed in a letterbox format, with black lines on the top and bottom of the
screen. Another factor on how a digital TV image is displayed is the actual size
of the screen. Basically you can fit more dots on a 50-inch Plasma Screen than a
27-inch Direct View DTV.
In current digital TV standards, there are a total of 18 video scan rates
that are approved by the FCC for use in the U.S. system. Fortunately, for the
consumer, and for this Guide, there are only three that are commonly used. The
three vertical scan line systems used in digital TV are 480p (480 lines
vertically scanned in a progressive fashion), 720p (720 lines vertically scanned
in a progressive fashion), and 1080i (1,080 lines scanned in an interlaced
fashion).
HDTV vs EDTV
So, even though you may be inputting a 1080i image into your HDTV, your TV may
not have the ability to reproduce all the dots within those lines. In this case
the signal is often reprocessed (up converted or down converted) to conform to
the number and size of dots (pixels) on the physical screen. At full resolution
on a 16x9 screen, a 1080i image is comprised of 1920x1080 pixels (about a
two-mega pixel field).
However, if your monitor is not capable of reproducing the total pixel field,
then the image is scaled to fit the number of pixels in the display monitor's
pixel field. So, an HDTV image of 1920x1080 can be scaled to fit 1366x768,
1280x720, 1024x768, 852x480, or other pixel field. The relative loss of detail
actually experienced by the viewer will depend on factors such as screen size
and viewing distance from the screen.
In essence, when purchasing an HDTV, it is not only important to make sure that
you can input 480p, 720p, or 1080i signals, but you must also consider the pixel
field of the monitor itself (and whether up conversion/down conversion is used).
EDTV Plasma
To go on further detail on this, televisions that have to down convert an HDTV
signal (such as 720p or 1080i) to a pixel field of 852x480 (480p) for example,
are referred to as EDTVs and not HDTVs. EDTV stands for Enhanced Definition
Television. Specifically, If you check the newspaper or internet ADs for
"bargain priced" Plasma televisions, for instance, you will notice that they are
often EDTVs and not HDTVs. These sets can accept HDTV input signals, but must
down convert them to EDTV resolution to display them on the screen.
EDTV Video Projection
In addition to EDTV plasma television, budget-priced video projectors often are
capable only of EDTV resolution and are not capable of projecting a true
HDTV-resolution image. Just as with EDTV plasma televisions, budget video
projectors will often have the capability of inputting an HDTV signal through
HD-component, DVI, or HDMI input connections. However, if the projector has a
native pixel resolution of 640x480, 852x480 or 1024x768, the video projector
will have to scale a 1080i (1920x1080) or 720p (1280x720) HD image down to fit
its lower native pixel resolution, in order to project it onto the screen.
Resolution Requirement For True HD Image Display
On the other hand, if televisions or video projectors convert 1080i signals to
720p, they are still referred to as meeting HDTV specs. Most LCD flat panel
televisions, for example, currently have a native pixel resolution of 1280x720
(720p). So, when faced with a 1080i (1920x1080) input signal, the LCD television
will convert (scale) the signal to 720p to display it on the screen. Since the
scaling is within the HDTV spec, the television is correctly labeled as an HDTV.
Basically, if a television or video projector has a native pixel resolution of
1280x720 or higher, it definitely has true HDTV resolution capability
A. With the advent of high
definition television, the development of components to match the resolution
capabilities of HDTV are becoming more important. As a solution, more and more
DVD players are equipped with "upscaling" capability to better match the
performance of the DVD player with the capabilities of the today's HDTV's.
However, the introduction of Blu-ray and HD-DVD
has confused the issue regarding the difference between the upscaling of
standard DVD and the true high definition capability of Blu-ray and HD-DVD.
For an explanation of DVD video upscaling and
how it relates to true high definition video, such as Blu-ray and HD-DVD, keep
on reading...
Standard DVD Resolution
A standard DVD player, without upscaling, can
output video resolution at 720x480 (480i). A progressive scan DVD player,
without upscaling, can output 720x480 (480p - progressive scan) video signals.
480i represents 720 pixels displayed
across a screen horizontally and 480 pixels down a screen vertically. This
arrangement yields 480 horizontal lines, which are, in turn, displayed
alternately. In other words, all the odd lines are displayed, followed by all
the even lines.
480p represents 720 pixels displayed
across the screen horizontally and 480 pixels down the screen vertically. This
arrangement yields 480 horizontal lines on the screen, which are, in turn,
displayed progressively, or each line displayed following another.
The Upscaling Process
Upscaling is a process that mathematically
matches the pixel count of the output of the DVD signal to the physical pixel
count on an HDTV, which is typically 1280x720 (720p) or 1920x1080
(1080i - and, some cases, 1080p).
720p represents 1,280 pixels displayed
across the screen horizontally and 720 pixels down the screen vertically. This
arrangement yields 720 horizontal lines on the screen, which are, in turn,
displayed progressively, or each line displayed following another.
1080i represents 1,920 pixels displayed
across a screen horizontally and 1,080 pixels down a screen vertically. This
arrangement yields 1,080 horizontal lines, which are, in turn, displayed
alternately. In other words, all the odd lines are displayed, followed by all
the even lines.
1080p, on the other hand, represents
1,080 horizontal lines displayed sequentially. This means all lines are
displayed during the same pass. 1080p is the highest quality HD display
format.
The Practical Effect Of DVD Upscaling
Visually, there is very little difference to
the eye of the average consumer between 720p and 1080i. However, 720p can
deliver a slightly smoother-looking image, due to the fact that lines and
pixels are displayed in a consecutive pattern, rather than in an alternate
pattern.
The upscaling process does a good job of
matching the upscaled pixel output of a DVD player to the native pixel display
resolution of an HDTV capable television, resulting in better detail and color
consistency.
However, upscaling, as it is currently
implemented, cannot convert standard DVD images into true high-definition
images. In fact, although upscaling works well with fixed pixel displays, such
as Plasma and LCD televisions, results are not always consistent on CRT-based
high definition televisions.
Points to Remember:
1. Any DVD player can be hooked up to an
HDTV. Although upscaling DVD players are better able to match the native pixel
resolution of an HDTV, you will still get good results on a standard DVD
player that is connected via an HDTV's provided Component or S-Video inputs.
2. If you DO have an HDTV, and a
standard DVD player, you will get the best results using the Component video
connection (red-blue-green) between the DVD player and the HDTV. In addition,
if your DVD player is progressive scan capable, always use that option when
connected to a progressive scan capable television.
3. DVD video upscaling is only an
approximation of the high definition viewing experience. To get the full
impact of true high definition viewing from a disc format, you need to have
either a Blu-ray or HD-DVD player connected to an HDTV via an HDMI connection
and be viewing actual Blu-ray or HD-DVD disc content.
This is just a few of the cutting-edge technology tools Expos4Products.com can
provide to help meeting planners keep pace with rapidly changing demands. For
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About Expos4Products.com
Expos4Products Computer & AV Solution providers has remained a leading provider
of computer and audio visual rental equipment, offering service throughout the
U.S. Industries such as entertainment, technology, health care and advertising
rely on Expos4Products for fast, reliable, cutting-edge technology rentals and
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More next month...
Best wishes,
"There is marketing that snores or bores. Then there
is marketing that roars. Make your marketing roar!"
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