Sony DVP-NS999ES - Manual (Page 45)

ES Series DVD-Video/CD/SA-CD Players; Version 3.0 Page 45
or 480i (when discussing the line rate) or 60i (when discussing the picture rate).
The 480i solution is a compromise that doubles the picture rate but halves the
vertical resolution at any given instant. While it is a compromise, the 480i system
is highly effective, an elegant engineering solution that has helped make
television an essential part of entertainment.
Interlace scanning divides the frame into two "fields." The first field
presents the odd-numbered scanning lines (1, 3, 5, etc.). The second
field presents the even-numbered lines. Compared to progressive
scanning, picture quality is reduced and the horizontal scanning lines
are far more prominent on the screen.
In the early days of television, when 12-inch diagonal screens were
commonly used in living rooms, halving the vertical resolution was not a practical
concern. But in today's environment of 61-inch diagonal projection systems, the
illusion of a continuous picture on the screen begins to fall apart. Depending on
how close you sit to the screen, individual scanning lines become visible and the
compromise in vertical resolution becomes an annoyance. That's why many of
today's finest big screen televisions have the ability to input and display 480P at
60 frames per second—480/60P. When carefully executed, 480/60P can
achieve fluid, lifelike fast motion, along with breathtaking image detail. The
480/60P system is also superb for resolving fine print on the screen—one reason
why 480/60P is the basis of the popular VGA computer display standard.
Film and video origination
Movie film is conventionally shot and displayed at 24 frames per second.
In the camera, the entire frame of film is exposed at one time. In the theater, the
entire frame is projected at one time. Unfortunately, projecting at the native film
rate of 24 frames per second creates flicker. That's why movie projectors use a
special shutter to display each frame twice, creating the effect of 48 frames per
second.