Sony DVP S9000ES Bedienungsanleitung PDF herunterladen (Seite 4)

In 1997, Sony’s original DVP-S7000 helped launch the DVD-

Video format and was quickly acclaimed as the “Reference

Standard.” In 1998, the second-generation DVP-S7700 took

DVD playback to a new level of accuracy. Of course, both

players were designed to maximize performance with the huge

universe of televisions using 525-line interlace scanning.

In the mean time, TV stations have launched the era of Digital

Television (DTV) broadcasting. High Definition satellite

broadcasting has become a commercial reality. In response,

Sony and others have introduced a growing population of

televisions with higher scanning frequencies, capable of better

than 525-line interlace scanning.

Some of these new televisions offer progressive scan or 525P

inputs, which can accept 525P output from a DVD player. And

525P outputs have quickly been promoted as a must-have feature

in high-end DVD players. They promise reproduction that’s

even more detailed, more natural, more film-like.

However, there are important differences in how DVD players

process the 525P signal. Circuitry varies greatly in sophistica-

tion and cost. To appreciate the technology behind these

differences, readers need a firm understanding of progressive

versus interlace scanning, film versus video origination, 3-2

pulldown and 3-2 reverse conversion. This section reviews

these basic issues.

In video, what appears to be a continuously moving image is

actually a series of discrete still pictures, called frames. On the

typical direct-view television, each frame is created on the

picture tube by an electron beam that moves from the left edge of

the screen to the right, illuminating one scanning line at a time.

The American EIA television system uses 525 total scanning lines

per frame.

Due to bandwidth limitations from the early years of television,

the NTSC system was designed to capture 30 frames per second.

The natural way to display these images would be to show the

scanning lines in sequence, an approach called progressive

scanning. 525-line progressive scanning at 30 frames per

second is abbreviated 525/30P or simply 525P. Unfortunately,

525/30P creates flicker: the image visibly darkens between

frames. In addition, capturing images at 525/30P yields

unsatisfactory results in fast-paced action like live sports.

For these reasons, the early television engineers developed a

solution called interlace scanning. Instead of capturing and

displaying all 525 lines in their numerical sequence, the NTSC

system divides the image into two fields. The “A” field contains

the odd-numbered scanning lines (1, 3, 5, etc.) and lasts 1/60

second. The “B” field contains the even numbered lines and lasts 1/60

second. This system can be abbreviated 525/60i or simply 525i

(when discussing the line rate) or 60i (when discussing the picture

rate). The 525i solution is a compromise that doubles the picture rate

but halves the vertical resolution at any given instant. While it is a

compromise, the 525i system is highly effective, an elegant

engineering solution that has helped make television an essential part

of entertainment.

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, especially when you sit close 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 525P at 60 frames per second (525/60P). When carefully

executed, 525/60P can achieve fluid, lifelike fast motion, along with

breathtaking image detail. The 525/60P system is also superb for

resolving fine print on the screen — one reason why 525/60P is the

basis of the popular VGA computer display standard.

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.

Theatrical release movies aren’t the only programs that are

originally captured at 24 frames per second on motion picture

film. The following is a snapshot of common industry practice:

Genre Typical Origination

Theatrical release movies 24P film

Made for TV movies 24P film

Hour-long primetime dramas 24P film

Music videos 24P film

Network commercials 24P film

Sitcoms Either

Documentaries Either

Network news magazines Either

Live concerts 60i video

Wildlife/natural history 60i video

Reality-based shows 60i video

Do-it-yourself series 60i video

Soap operas 60i video

News 60i video

Talk shows 60i video

Sports 60i video

Local Commercials 60i video

A Major New Opportunity

Film and Video Origination

Progressive and Interlace Scan

Fig. 1: Progressive scanning creates

the picture by illuminating each line

from top to bottom until all scanning

lines in the frame are completed.

Fig. 2: 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.

1 2 3 4 5 6 7 8 9 ... 19 20

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