Glossary

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a

ADSL

ADSL

ADSL designed to download data three to four times faster than it uploads, an ADSL (asymmetric digital subscriber line) internet connection is beneficial to users who download more data than they upload. Commonly configured to download at 1.544 Mbps and to upload at 128 Kbps.

Advanced Pull-down

Advanced Pull-down

Refers to a new method of applying pull-down (q.v.). This pull-down has a different cadence of 2:3:3:2, which enables the 3rd of each sequence of 5 video frames to be removed, in order to restore the proper rate of 24 fps.

Algorithm

Algorithm

An algorithm can refer to any fixed series of steps, e.g. a recipe. Most computer programs function by following these step-by-step patterns, written in a computer language. For computer programmers algorithmic simplicity is the goal.

Aspect ratio

Aspect ratio

Size of the active part of the TV picture given as width:height ratio. Traditional TV (Standard Definition) uses 4:3, but SD may also use 16:9. High Definition is always 16:9.

b

Bandwidth

Bandwidth

The speed that data transfers through an internet connection, measured in bps (bits per second). The faster the better.

Bits and bytes

Bits and bytes

An abbreviation of binary digit, 1 bit (b) is the smallest unit of computer data.
1 byte (B) = 8 bits
1 kilobyte (KB) = 1024 bytes
1 megabyte (MB) =1024 kilobytes
1 gigabyte (GB) = 1024 megabytes

bps

bps

Standing for bits per second, this is the unit of measurement for bandwidth. Faster data transfer speeds are more commonly measured in Kbps (kilobits per second – thousands of bits per second), Mbps (megabits per second – millions of bits per second) and Gbps (gigabits per second – billions of bits per second).

Broadband

Broadband

Meaning broad bandwidth, a broadband internet connection can transfer data up to 20 times faster than conventional narrowband and is necessary for high data transfer activities like videoconferencing. There are a few ways of connecting to the internet at broadband speeds: see DSL, ADSL, SDSL, cable broadband and satellite.

c

Cable broadband

Cable broadband

A broadband internet connection that uses a cable modem to connect a computer to a coaxial cable-TV line. Data is transferred at a similar speed to a DSL connection.

Camera

Camera

A picture-taking device usually consisting of a light-tight box, a shutter to admit a measured quantity of light, and a lens to focus the image. The light is usually recorded on film or electronically on chips.

CMS

CMS

Standing for content management system, this is software that allows the smooth management of a website’s content, for instance, by facilitating the process of uploading new information to a site.

Codec

Codec

The name derived from file compression-decompression, codecs are computer programs that compress and decompresss different types of files.

Contention ratio

Contention ratio

To reduce costs, internet connections along telephone lines may be shared by several disparate users. A connection shared by 50 people has a contention ratio of 50:1. If all 50 went online at the same time, it would slow to a crawl for all of them.

Cross-conversion

Cross-conversion

Conversion of one HD line scan system to the other (with different pixel numbers), for example 720 line HD to 1080 line HD or vice versa.

d

Decoder

Decoder

A computer program necessary to convert an encoded file back to its original form.

Delta frames

Delta frames

Frames that contain all the data (pixels) that differ from the previous frame. They work in conjunction with key frames.

Dial-up

Dial-up

A temporary connection to the internet via a standard telephone line and modem, as opposed to the ‘always on’ connection of broadband.

DNxHD

DNxHD

Avid’s HD codec used on their HD editing products. Various compression settings are possible, the highest producing similar compression rates to HDCAM and HDDVCPRO.

Down-conversion

Down-conversion

Conversion of either 720 or 1080 line HD images to Standard Definition. This may also involve aspect ratio conversion.

Downloads

Downloads

Any data that is transferred from the internet down to your computer. See uploads.

e

Encoder

Encoder

A computer program that converts one file type into another. It could be a WAV audio file compressed into an mp3 audio file.

f

File compression

File compression

Compressing files with the appropriate software makes them smaller so they take up less memory space on a hard drive and can be transferred over the internet faster.

Frame

Frame

The individual pictures that comprise a video. They are played back so fast that the images appear as continuous motion.

Frame rate

Frame rate

Measured in frames per second, frame rate is the number of pictures (or frames) per second displayed during video playback. The faster the rate, the smoother the playback.

FTP

FTP

File transfer protocol (FTP) is the standard system for transferring files over the Internet.

h

HDCAM

HDCAM

Sony’s HD video format based on Betacam-sized cassettes. Supports the 1080 line format at various frame rates. Some HDCAM decks will also play Betacam SP and Digibeta tapes. Being superseded by HDCAM SR.

HDDVCPRO

HDDVCPRO

Panasonic’s HD format using DVCPRO tapes. Can be 720 or 1080 line format at various frame rates. Compression rate similar to HDCAM.

HDV

HDV

Two flavours of HD, supported by various manufacturers, recorded onto DV-sized cassettes at DV data rate of 25Mb/s. HDV1 is 720 line, HDV2 is 1080 line. Uses MPEG2 compression for the video and MP2 compression for the audio.

High Definition

High Definition

Term used to describe TV systems with 1280 x 720 or 1920 x 1080 pixel resolution.

HTTP

HTTP

Hypertext transfer protocol (HTTP) is the standard system for transferring the data of web pages down to the internet user.

i

Interlaced Scan

Interlaced Scan

System used in all traditional TV images, whereby each frame is separated into 2 field scans consisting of alternate scan lines down the picture. Each is field is captured at a separate moment in time, resulting in smoother motion portrayal than is possible with film.

IP

IP

Standing for internet protocol, IP defines the standard methods by which data is transferred over the internet.

IP address

IP address

This is a sequence of four sets of numbers, each set separated by a period, e.g. 218.73.976.131. Any computer connected to the internet will be represented online via a unique IP address, assigned to the computer by the ISP.

ISDN

ISDN

Using a standard telephone line with an adaptor instead of a conventional narrowband modem, an ISDN (integrated services digital network) internet connection transfers data at up to 128 Kbps. Not broadband speed and not fast enough for most businesses.

ISP

ISP

You’ll need to set up an account with an ISP (internet service provider) in order to access the internet. These companies, like BT and AOL, offer a range of internet access options.

j

JPEG

JPEG

Stands for the Joint Photographic Experts Group. The group set a standard mechanism for image file compression.

k

Key frames

Key frames

Frames used in video file compression to eliminate surplus data. Though regularly refreshed, they reduce file size by working in conjunction with delta frames to cut out data (pixels) that is common to successive frames.

l

Leased line

Leased line

A telephone line that is leased from a telecommunications company to link permanently to the internet. Typically leased to connect several networked terminals. Very expensive.

m

Modem

Modem

A piece of hardware that converts digital signals from a computer to the analog signals that can travel along a standard telephone line, and vice versa.

MP3

MP3

Otherwise known as an MPEG-1 audio layer 3, an mp3 is the MPEG standard mechanism for audio file compression.

MPEG

MPEG

Stands for the Moving Pictures Experts Group. The group devised a set of standard mechanisms for video and audio file compression. MPEG-1 is the standard for CD-ROM video and audio. MPEG-2 is the standard for broadcast quality video. MPEG-4 is the standard for video telephony.

Multicasting

Multicasting

Broadcasting information, such as audio or video, over the internet to multiple selected recipients. Unlike webcasting, only those selected to receive the multicast can access the information.

n

Narrowband

Narrowband

Using a standard telephone line with a conventional narrowband modem, this is the traditional method of connecting to the internet, transferring data at up to 56 Kbps. Most users will find it too slow and will yearn for broadband.

NTSC

NTSC

Standing for National Television Systems Committee, this is the colour television analog broadcast standard in the US. NTSC sends analog video signals of 525 lines of resolution per frame at 30 frames per second. Video adapters are available that convert the analog signals into digital signals, enabling computer monitors to be used as television screens, and vice versa. See PAL and video fields.

p

P2

P2

Panasonic’s tapeless format enabling recording of SD or HD images onto memory cards. Currently 8GB is the largest available P2 card size.

PAL

PAL

Standing for phase alternation line, this is the dominant colour television analog broadcast standard in Europe. PAL sends analog video signals of 625 lines of resolution per frame at 25 frames per second. Video adapters are available that convert the analog signals into digital signals, enabling computer monitors to be used as television screens, and vice versa.

Pixel ratio

Pixel ratio

The ratio of the width to the height of a pixel. A square pixel has a pixel ratio of 1. A pixel twice as wide as it is high has a pixel ratio of 2:1.

Pixels

Pixels

Digital images are comprised of many tiny coloured pixels. Each pixel should be too small to distinguish unless the image is over-enlarged. The basic rule is the more pixels comprising an image, the better it will appear.

Podcast

Podcast

The term refers to audio files published to the web along with a news feed (RSS), letting users subscribe to a series of shows and download them automatically.

Progressive Scan

Progressive Scan

System whereby the entire image is scanned in one pass from top to bottom, without interlace (q.v). Produces an image in a similar way to telecine’d film.

PsF

PsF

Progressive segmented Frame. HD format used to convey a progressive scanned image between certain types of interlace-compatible equipment. Image scanning is divided into interlaced fields, then re-assembled.

Pull-down

Pull-down

Usually refers to system of adding a field to alternate frames of 24fps film when converting to NTSC video (29.97fps). This results in a 3:2 cadence to the image motion, and a 0.1% slow down in the frame rate.

q

QuickTime

QuickTime

Multi-media program developed by Apple for Mac and PC users. Single QuickTime files are able to combine many media forms, e.g. audio, video, text and animation.

QuickTime VR

QuickTime VR

Stands for QuickTime Virtual Reality. An enhanced version of the standard QuickTime multi-media prgram from Apple, allowing 3D images to be viewed. There are two types of QTVR: panorama (immersive) and object. Panorama allows you to visually spin 360° in, for instance, a room, to look up and down and to zoom in and out. Object allows you to view and rotate a 3D image of an object as if it were in your hand.

r

Rate conversion

Rate conversion

Conversion of images from one frame rate into a different one, such as 25fps to 30fps. The term is used with HD images as no pixel conversion is necessary.

RealAudio/RealVideo

RealAudio/RealVideo

A client-server software system and file format (by RealNetworks) which allows Internet users to play streamed audio/video-based multimedia content from the Internet

RealMedia

RealMedia

RealMedia is the collective term for RealAudio and RealVideo

RSS

RSS

Aka Really Simple Syndication. It is the most popular news feed syndication format; RSS 2.0 is the defacto feed format for podcasting

RTSP

RTSP

Standing for Real Time Streaming Protocol, it is a standard from RealNetworks for controlling the delivery of streaming multi-media data from the internet. Designed for webcasting.

s

Satellite broadband

Satellite broadband

An internet connection via a satellite communications network. It is an ‘always-on’ connection that is not dependent on cable or telephone lines.

SDSL

SDSL

SDSL is designed to download and upload data at the same speeds; an SDSL (symmetric digital subscriber line) internet connection is valuable to businesses that upload as much data as they download. Expect transfer speeds of 384 Kbps. See ADSL.

sRGB

sRGB

Colour profile system used by many graphics packages and also HDTV.

Standard Definition

Standard Definition

Term recently coined to describe the traditional TV system in use for the past half-century, as distinct from newer High Definition TV.

Standards Conversion

Standards Conversion

Conversion of frame rate and line scan system from one video standard to another, such as PAL to NTSC. Involves creating new frames and converting pixels.

Streaming

Streaming

Technology that allows users to watch video or listen to audio data live through the Internet, rather than waiting for whole files to be downloaded before they can be played. It’s employed in videoconferencing, video telephony, webcasting and multicasting.

StuffIt

StuffIt

The standard file compression program for Macintosh users. A version is now available for PC users too: see WinZIP.

Super 16

Super 16

Formerly popular film format for high-end TV genres, such as drama. Uses 16mm gauge film with a wider image area than conventional 16mm, and 15:9 aspect ratio. Being superseded by HD.

u

Up-conversion

Up-conversion

Conversion of Standard Definition images to either 720 or 1080 line HD. This will involve a decision as to how to re-format a 4:3 image.

Uploads

Uploads

Any data that is transferred from your computer up to the internet. See downloads.

v

Varicam

Varicam

Panasonic’s 720 HD camera capable of running at any frame rate from 4 to 60 frames per second. Slower frame rates are similar to ‘under-cranking’ on a film camera and result in high-speed motion on playback at a normal rate of 25 or 30fps. High frame rates produce the opposite effect. Separate frame rate converter required for playback.

Video conferencing

Video conferencing

Becoming increasingly popular, video conferencing is video telephony technology allowing two or more individuals, or businesses, to communicate in real time with each other via computer and a camera.

Video fields

Video fields

PAL and NTSC send colour television analog signals at 25 and 30 frames per second respectively. In fact, each of these frames is sent in two half-frames, or video fields.

Video telephony

Video telephony

Audio and visual communication between two participants in real time. It requires a very broad bandwidth to handle video data, and current technology does not allow video telephony without some compromise on the standard of the video quality. A webcam and microphone, and a monitor and speakers are required at each end to transmit and receive the video and audio data.

w

Web 2.0

Web 2.0

The phrase was coined by O'Reilly Media in 2003 in reference to a perceived second generation of web-based communities and hosted services — such as social-networking sites (eg.Facebook, Bebo, Myspace, etc), wikis and folksonomies — which facilitate collaboration and sharing between users.

Webcam

Webcam

A basic digital camera intended to exist as part of your computer set up. It might record still and/or moving images for upload to the internet. See videoconferencing and video telephony.

Webcasting

Webcasting

Broadcasting information, such as audio or video, over the internet. Many radio stations, for example, are using this technology. A webcast may be live or pre-recorded.

Weblog

Weblog

A website, usually built with user-friendly web content management systems, that feature chronologically arranged entries.

Windows Media Player

Windows Media Player

Made by Microsoft, Windows Media Player (WMP) is supplied as standard with Windows operating systems. it supports Single bit rate and multibitrate streams. The player is free, and it is not necessary to pay a licence fee to create or distribute Windows Media format files. WMP is for video with, or without audio. WMA is a format specifically for streaming audio-only files.

WinZip

WinZip

The standard file compression program for PC users. See Stuffit for Macintosh users.

x

XDCAM

XDCAM

Sony’s tapeless format enabling recording in the camera to 23GB optical disks known as Professional Disks (PD).