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GLOSSARY


ATSC Tuner
Allows reception of DTV (digital television) signals broadcast over-the-air (OTA) by local television stations. The FCC requires ATSC tuners in all television sets and interface devices devices with tuners manufactured after a certain date, but does not require QAM tuners.

Anamorphic Widescreen
Originally a cinematography technique for capturing a widescreen picture on standard 35mm, now more popularly used to refer to a technique for maximizing picture quality in DVDs. Anamorphic widscreen DVDs store a stretched picture instead of storing black letterboxing bars, allowing for a 16:9 aspect ratio instead of the standard 3:4 aspect ratio. If the DVD player is set up to output a widescreen image, the horizontally squeezed image is sent to the display device where it is stretched to fill the wider screen; if the player is set up to output a letterboxed picture, the player will stretch the picture and add letterbox black bars before sending it to the display device. See also Letterbox, Pan and Scan.

Codec
Short for compression-decompression, a codec is a mathematical formula that analyzes the data in a file and determines how data can be removed while still maintaining an acceptable file quality. By removing data, the file becomes much smaller (i.e., compressed). The dropped data is replaced by the formula so that on the playback side it can be recreated (i.e., decompressed).

Blu-ray
A rewritable optical disc holding two hours of high-definition video or twelve hours of standard video. Announced in 2002, Blu-ray technology uses a blue-violet laser capable of reading smaller pits, resulting in a higher density.

Dual Layer
Two sandwiched layers on a DVD side, allowing twice the recording time as available on a "single layer" DVD. Some dual-layer DVDs use an RSDL ("reverse spiral dual layer") configuration so the player reads the top layer from the center of the disc outward and the bottom layer from the outer edge inward, usually resulting in a slight pause when switching from the top to the bottom layer. Generally speaking, the data surface is golden colored on dual-layered DVDs and silver on single-layer DVDs.

Letterbox
A technique whereby widescreen films are copied to video/DVD formats preserving the original aspect ratio. Since the video/DVD display may be more square than the original film, the copy includes a masked-off area (black bars) above and below the picture so only part of the display screen is used. See also Anamorphic, Pan and Scan.

NTSC
Short for National Television Systems Committee, the group responsible for setting television and video standards in the U.S. The video standard in the U.S., also referred to as NTSC, broadcasts 525 lines of resolution per second.See also PAL, SECAM.

PAL (Phase Alternate Line)
The television broadcast standard throughout most of Europe. The standard broadcasts 625 lines of resolution (The NTSC standard in the U.S. broadcasts 525 lines of resolution). See also NTSC, SECAM.

Pan and Scan
A technique for adjusting widescreen films by cropping the original image so the film can be shown on a standard television screen with a 4:3 aspect ratio. During the process a technician selects the parts of the original filmed composition that seem most significant and makes sure they are copied. See also Anamorphic, Letterbox.

Progressive Download
A type of streaming in which the audio or video file begins to play after a certain minimum amount of data has been transferred, rather than requiring the entire file to be downloaded before playback starts. A local copy is stored after download.

QAM (Quadrature Amplitude Modulation)
A method of combining phase-modulated and amplitutde-modulated signals into a single channel, thereby doubling the effective bandwith, often used to transmit digital cable TV and cable Internet service signals. Televisions with QAM tuners allow you to receive unscrambled HD for a cable provider without a set-top box.

Region Codes (DVDs)
DVDs are encoded for operation in one of eight geographical regions and players manufactured in any region can only play DVDs encoded for operation within that region. The U.S. and Canada comprise Region 1. There are also some "Region 0" discs which are uncoded and may be played in any region, but Region 0 PAL discs must be played on a PAL-compatible player and Region 0 NTSC discs must be played on an NTSC-compatible player.

Replication
A professional process that creates a CD/DVD by molding the disk to be an exact copy of the original master.

SECAM (Séquentiel Couleur à Mémoire)
The television broadcast standard in France, the Middle East, and most of Eastern Europe. The standard broadcasts 819 lines of resolution per second (The NTSC standard in the U.S. broadcasts 525 lines of resolution). See also NTSC, PAL.

Streaming
Delivering a file from a server in "real time," i.e., playing a file as it is being downloaded. Streaming media files begin to play immediately and are discarded after playback is complete, so no permanent storage is needed on the viewer's hard drive.

Video on Demand (VoD)
A system which allow users to select and watch video content over a network as part of an interactive television system.

Webcasting
The entire process or all the steps in producing a webcast event...from capture and encoding of content, to web development, to creation of players and other tools, through to delivery to the audience.


























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