文档介绍：Digital Video Editing
18-04-2004
THE VIDEO BASICS
DVD Video Training in Adobe Premiere Pro .COM
THE VIDEO BASICS
Video Signals:
Analog signals are made up of continuously varying waveforms. In
other words, the value of the signal, at any given time, can be
anywhere in the range between the minimum and maximum allowed.
Digital signals, by contrast, are transmitted only as precise points
selected at intervals on the curve.
The type of digital signal that can be used by puter is binary,
describing these points as a series of minimum or maximum values -
the minimum value represents zero; the maximum value represents one.
These series of zeroes and ones can then be interpreted at the
receiving end as the numbers representing the original information.
THE VIDEO BASICS
Frame Resolution:
PIXELS (Picture Elements) is the minimum screen display element,
represented as a point with a specified color and intensity level (RGB
or YCC).
FRAME is a single still image in a sequence of images (Video).
FRAME
FRAME RESOLUTION is the amount of information (PIXELS) in
PIXEL each frame.
640
320
240
320 X 240 480
640 X 480
Higher resolution will result in a better quality image and more storage required.
THE VIDEO BASICS
Frame Aspect Ratio:
Width
The Frame Aspect Ratio describes the ratio of width to height in the
dimensions of a frame. For example, the frame aspect ratio of NTSC
video is 4:3, and some motion-picture (Film) frame sizes use the
Height more elongated aspect ratio of 16:9.
Frame Aspect Ratio
4 16
3
9
4:3
16:9
THE VIDEO BASICS
Pixels Aspect Ratio:
Pixels Aspect Ratio:
Some video formats use a different aspect ratio for the pixels that
Square Pixels (),
make up the frame. When a video using square pixels is displayed
DV NTSC (),
on a non-square pixel system, or vice versa, shapes and motion
DV PAL (),
appear stretched. For example, circles are distorted into