|
|
- Aspect Ratio -
The Long
and Short of It
- Aspect ratio is the width to height ratio of
either the program you are watching or the monitor you are
watching the program on. DTV sets are sold in two aspect ratios,
4:3 and 16:9. Don’t confuse screen size, the screen's diagonal
measurement, with aspect ratio.
|
- 4:3 DISPLAY
The
traditional TV is 4 units wide by 3 units high. Many TV shows and TV Networks still use this format.
A 16:9 program viewed on a 4:3 TV either creates black bars on the top and bottom or cuts off much of the
picture on the sides. This is SDTV, Standard Definition.
-
- 16:9 DISPLAY
16:9 is the aspect ratio of Wide
Screen TV's. They are 16 units wide by 9 units across. Both HDTV programs and TV's are 16:9.
A 16:9 program showing on a 16:9 screen fits perfectly, but is usually produced with the 4:3 viewer in mind
keeping important information in the mid area of the screen. DVD's viewed on a 16:9
screen may show black bars on the top and bottom because of the
wider than 16:9 theater aspect ratio of Hollywood movies. |
- Scanning and Pixels
- Images viewed on TV screens are
made up of small picture elements known as 'pixels. Resolution is
the quality of the picture displayed on the TV screen determined
by the scanning method and the number of pixels. The more pixels
in a display the higher the resolution. An individual monitors
native resolution is its pixels count. If the source has more
pixels than the display (the displays native resolution)
some visible detail and sharpness will be lost from the original
source. If the source has fewer pixels than the native resolution
of the display the picture will not look any better than the
original source picture.
|
- SCANNING
- SCANNING
METHOD
|
- INTERLACED SCANNING
(i)
|
- PROGRESSIVE SCANNING
(p)
|
- DESCRIPTION
|
- The lines are created in
two fields. Odd fields are scanned in the first 1/60th of
a second with even fields in the second 1/60th of a
second. The complete frame is "redrawn" every 30th of a
second.
|
- Every line of pixels is
refreshed with every scan, so the complete frame is
"redrawn" every 60th of a second.
|
- WHERE USED
|
- Analog NTSC and Digital
TV's
|
- Digital TV's and Computer
Monitors
|
- WHO USES
|
- All NTSC Analog cable
networks (480i), CBS and NBC networks (1080i). True
Interlaced HDTV is 1080i at 1920 x 1080 pixels.
|
- ABC, FOX and PBS networks
and ESPN. True Progressive HDTV is 720p at 1280 x 720
pixels.
|
- ADVANTAGE
|
- 1080i delivers more
information than 720p producing sharper pictures when the
image is "still" or has little motion.
|
- A complete image is
displayed on the screen two-times more often. Fast moving
action and graphics don't blur.
|
.
- PIXELS
- DISPLAY FORMAT
|
- PIXELS
|
- TOTAL
|
- HOW MUCH WILL BE
DISPLAYED
|
- ANALOG (NTSC)
|
- 480 x 525
|
- 252,000
|
- Is 440 x 480 and not every
pixel of VHS, DVD, Analog Cable or HDTV.
|
- EDTV -OK
|
- 852 x 480
|
- 408,960
|
- Every pixel of DVD, but not
HDTV.
|
- HDTV-GOOD
|
- 1,024 x 768
|
- 786,432
|
- Not every pixel of 720p or
1080i HDTV
|
- HDTV-GOOD
|
- 1,024 x 1,024
|
- 1,048,576
|
- Not every pixel of 720p or
1080i HDTV
|
- HDTV-BETTER
|
- 1,280 x 720
|
- 921,600
|
- Every pixel of 720p, but of
1080i HDTV
|
- HDTV-BEST
|
- 1,920 x 1,080
|
- 2,073,600
|
- Every pixel of both 720p or
1080i HDTV
|
| |
|
