Glossary

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A

AC-3

Dolby Digital Surround Sound System. A digitally compressed audio format characterized by its ability to offer as many as six separate digital audio channels. AC-3 is used for DVD-Video titles in the NTSC format. PAL titles use MPEG-2 audio compression standard.

Artifacts

Unusual or unwanted. Examples of artifacts include flicker, jitter, degradation of resolution, and aspect ratio abnormalities.

B

Bandwidth

The amount of data that can be transferred or processed per unit of time. In simple terms bandwidth is like pipe size - the larger the pipe, the more it can carry.

Bitrate

The data rate of the DVD title, expressed in Mbs (megabits per second). DVD bitrates are usually between 2 and 10 Mbs. The higher the bitrate, the more CPU required to playback the disc.

Brightness

The value of a pixel along the black-white axis. WinDVD allows the user to control the brightness of the video window.

C

CBR

Constant bit-rate. This type of compressed video signal uses the same amount of data to describe the video signal regardless of complexity.

Chapters

Video programs can be split up into titles, and then further into chapters. For example, on a disc with multiple sporting events; each event may be designated as a separate title. Each period in the individual sporting event or title may be designated a chapter.

Compression

Converting data into a more compact form for storage or transmission.

CSS

"Content Scramble System". The official DVD-Video digital encryption scheme. Only a CSS-licensed DVD player can unscramble the video data.

D

Data rate

The speed of a data transfer process, usually expressed in kilobytes (thousands of bytes) per second.

Decode

Decompressing a video clip and then converting its color.

Decompress

Converting video and audio data from a compressed form back into its original form.

Dolby Digital

* Dolby's multichannel audio format, also know as AC-3. Dolby Digital is a standard for DVD audio encoding.

DVD

An acronym for Digital Versatile Disc, an optical-disc technology developed by the DVD Consortium. There are five specified DVD disc varieties. DVD-ROM, DVD-Video, DVD-Audio, DVD-R (recordable), DVD-RAM (eraseable).

E

Encode

Converting the color space of a video clip from a full-bandwidth source to a compressed MPEG-2 file.

F

Field

One half of a video frame, consisting of every other scan line, in interlaced video content.

Frame

One video image in a series.

Frame rate

The number of frames per second at which a video clip is displayed.

Full motion video

Content that shows 30 (interlaced) or 24 (film content) frames per second.

G

Gigabyte

Literally, a billion bytes. A Gigabyte in DVD represents exactly 1 billion bytes of data.

H

Highlight

An active or focused subtitle. When you move your mouse pointer over a menu command, that command often changes color. It is then the "highlighted" subtitle.

I

Interlacing

Drawing a frame by alternately drawing the rows of each field. For example, an NTSC broadcast is expressed as 30 frames per second, but is actually made up of 60 half-frames displayed one after the other. The alternative is de-interlacing, where only complete frames are drawn on the screen.

J

Jitter

The smoothness of frame delivery over time.

L

Luminance

The part of a video signal that includes information about its brightness.

M

MPEG

Motion Picture Expert Group. MPEG-1 is used on video CD and CD-I as a video distribution medium. MPEG-2 and DVD offer better-than-laserdisc quality and twice the runtime per disc.

MPEG Audio

Compressed audio for use on DVD projects. PCM or MPEG stereo audio is required for PAL countries for DVD, but MPEG-2 audio is optional worldwide.

Multimedia

Any format that contains more than one media, such as text, still images, sound, animation, and video.

N

Navigation

Accessing the features of a DVD-Video disc using the specific commands.

NTSC

National Television Systems Committee. A committee of the Electronic Industries Association that prepared the standards for commercial television broadcasting in the United States, Canada, Japan, and parts of Central and South America. NTSC format has 525 scan lines (rows) of resolution at thirty frames per second (30 Hz).

P

PAL

Phase Alteration Line. This standard is used for commercial broadcasting in most of Europe, Australia, and parts of Central and South America. PAL format displays at 625 scan lines (rows) of resolution at 25 frames per second (25 Hz).

Pixel

Picture cell. This is the smallest independent unit of a digital image.

Pixel depth

The number of bits of color information per pixel.

R

Regional Coding

DVD players may be hard-coded to accept only DVD discs encoded for use in one of six designated world regions. This technique was developed to enable Motion Picture companies to release movies at different times in different regions.

Resolution

The number of pixels in the width and height of the video window.

S

Subtitle

Subtitles are the graphics displayed on top of video content. An example of a subtitle would be the menu choices displayed over the background graphic for many interactive games. When a subtitle is active, it is called a highlight. Subtitles are also the actual text of the content, displayed on the bottom of the screen. These subtitles are often used for language translations.

T

Titles

Video programs can be split up into titles, and then further into chapters. For example, on a disc with multiple sporting events; each event may be designated as a separate title. Each period in the individual sporting event or title may be designated a chapter.

V

VBR

Variable bit-rate. This allows DVD compression methods to use more or less compression according to the complexity of the picture.