Video in Multimedia

Video

Analog versus Digital:

Digital video has supplanted analog video as the method of choice for making

video for multimedia use. While broadcast stations and professional production and post-

production houses remain greatly invested in analog video hardware (according to Sony,

there are more than 350,000 Betacam SP devices in use today), digital video gear

produces excellent finished products at a fraction of the cost of analog. A digital

camcorder directly connected to a computer workstation eliminates the image-degrading

analog-to-digital conversion step typically performed by expensive video capture cards,

and brings the power of nonlinear video editing and production to everyday users.

Broadcast Video Standards

Four broadcast and video standards and recording formats are commonly in use

around the world: NTSC, PAL, SECAM, and HDTV. Because these standards and

formats are not easily interchangeable, it is important to know where your multimedia

project will be used.

NTSC: The United States, Japan, and many other countries use a system for broadcasting

and displaying video that is based upon the specifications set forth by the 1952

National Television Standards Committee. These standards define a method for

encoding information into the electronic signal that ultimately creates a television

picture. As specified by the NTSC standard, a single frame of video is made up

of 525 horizontal scan lines drawn onto the inside face of a phosphor-coated

picture tube every 1/30th of a second by a fast-moving electron beam.

PAL: The Phase Alternate Line (PAL) system is used in the United Kingdom, Europe,

Australia, and South Africa. PAL is an integrated method of adding color to a

black-and-white television signal that paints 625 lines at a frame rate 25 frames

per second.

SECAM: The Sequential Color and Memory (SECAM) system is used in France, Russia,

and few other countries. Although SECAM is a 625-line, 50 Hz system, it differs

greatly from both the NTSC and the PAL color systems in its basic technology

and broadcast method.

HDTV: High Definition Television (HDTV) provides high resolution in a 16:9 aspect

ratio (see following Figure). This aspect ratio allows the viewing of Cinemascope

and Panavision movies. There is contention between the broadcast and computer

industries about whether to use interlacing or progressive-scan technologies.