VIDEO EDITING

Digital Video Fundamentals

Pixel -- The individual picture elements, or "dots" of color, that are arranged in a

two-dimensional array to define a digital image or video frame. The dimensions or

resolution of an image are described in terms of the horizontal and vertical pixel

count.

Resolution -- The dimensions of an image, in pixels, typically expressed as the

number of horizontal pixels across and the number of vertical pixels down. See also

aspect ratio.

Transcode -- To convert from one compression format to another (that is, from

DV video from a camcorder to MPEG-2 for DVD). Preferably done intelligently

to minimize loss of quality from repeated compression, and not requiring fully

decompressing the input and then recompressing to the output.

compress -- To reduce the size of audio or video data through the use of a

compression scheme. Also called encode. See also decompress, lossy, and lossless.

decompress -- To process a compressed bitstream and recover the original data (if

lossless compression), or an approximation of the original (if lossy compression).

Also called decode. See also compress.

Lossless -- Any compression scheme, especially for audio and video data, that uses a

nondestructive method that retains all the original information, and therefore does not

degrade sound or video quality.

Lossy -- Any compression scheme, especially for audio and video data, that removes

some of the original information in order to significantly reduce the size of the

compressed data. Lossy image and audio compression schemes such as JPEG

and MP3 try to eliminate information in subtle ways so that the change is barely

perceptible, and sound or video quality is not seriously degraded.

Perceptual compression -- A compression technique that takes advantage of

knowledge of how humans perceive; that is, by eliminating visual detail that the eye

cannot easily see or audio frequencies that the ear cannot easily hear.

Compressor -- Program by which files are compressed. A compressor that also

decompresses files (returns them to their original state) is called a codec. See also

compress.

Codec -- A video or audio compression component that can both compress and

decompress (encode and decode) files. Media formats and players, such as Windows

Media, RealMedia, and QuickTime have a selection of codecs built in, and can add

additional codecs to support new file formats. See also compression.

Digital Video Formats

DV -- A Digital Video tape and compression format for consumer and professional

video equipment. The DV compression format is used for DV and Digital-8

camcorders. DV format video and audio can be captured using a FireWire / IEEE

1394 interface and then saved and edited in a video editor. The consumer tape format

is more accurately called mini-DV. See also analog media.

FireWire -- A digital data interface standard that provides a high-speed Plug-and-

Play interface for personal computers. Used for connecting DV camcorders to

computers, as well as to hard disk drives and DVD drives. Supports up to 480 Mbps

data rate. Also known as IEEE 1394 and Sony iLink. See also USB.

FireWire connector -- A roughly rectangular, hot-pluggable connector used for

FireWire/IEEE 1394 digital connections, especially digital video signals such as from

DV camcorders. The connectors can vary in size: full-size (6-pin) for connecting

to a computer or hub, and smaller (4-pin) for connecting to equipment such as DV

camcorders. See also BNC connector, DV, F connector, RCA connector, S-Video

connector.

USB (Universal Serial Bus) -- A digital data interface standard providing a Plug-

and-Play interface for personal computers. Typically used for lower-speed peripherals

such as mice, keyboards, printers, and scanners. Also used for interfacing to digital

cameras. The existing USB 1 standard provides up to 12Mbps (million bits per

second) data rate. The new USB 2 standard supports up to 480Mbps data rate. See

also FireWire.

AVI -- Acronym for Audio Video Interleave. The old multimedia file format used

under Windows for interleaved video and audio streams. See also Video for Windows,

Windows Media.

Video for Windows -- The media file format used with Microsoft Windows (.AVI).

Supports many different video and audio compression formats (codecs). See also

Windows Media.

Windows Media -- The multimedia platform built into Microsoft Windows, and a

series of formats for storing and transmitting video and audio. Uses ASF, WMA, and

WMF file types. See also Video for Windows, Windows Media Audio and Windows

Media Video.

Windows Media Video (WMV) -- The Microsoft Windows Media format for

compressed video and audio files on CD and DVD discs. See also Windows Media

Audio.

QuickTime -- Multiplatform, multimedia Movie file format from Apple Computers

(.MOV).

RealMedia -- Multiplatform, multimedia Web streaming file format from Real

Networks (.RM, .RAM).

streaming media -- Internet video and/or audio clips that can play directly over

the Internet, without needing to be downloaded first onto a computer. Used to view

and hear broadcasts, and to interactively play and seek in stored clips. See also

progressive download.

progressive download -- A technique for downloading Internet video and/or audio

clips so that they can be viewed at the same time that they are being transferred

to your computer. This provides some of the benefits of streaming media without

requiring a special streaming server. See also streaming media.

MPEG -- A family of popular multimedia file formats and associated compression

schemes defined by the Moving Pictures Expert Group. MPEG-1 video was

designed for use on CD-ROMs and provides picture quality somewhat comparable

to VHS. MPEG-2 video was designed for consumer video and is used on DVD, and

can provide high-quality full-screen full-rate video with smaller file sizes. MPEG-4

video is designed for a broad range of multimedia applications, and is used for web

and wireless streaming video. MP3 is a commonly-used audio compression format,

especially for web downloads and portable music players.

MPEG-1 -- An older digital video compression format developed in the early 1990s

by the Moving Picture Experts Group. MPEG-1 video was designed for lower-

resolution video played from CD-ROM and provides picture quality somewhat

comparable to VHS (typically 352x240 resolution). Used for Video CD discs.

MPEG-2 -- A TV-quality digital video compression format developed in the mid-

1990s by the Moving Picture Experts Group. MPEG-2 video provides high-quality

full-screen full-rate video (720x480 resolution for NTSC) with smaller file sizes

than MPEG-1. Used for DVD discs, and also scales to high-definition resolution and

bitrates.

MPEG-4 -- A digital multimedia compression format developed in the late 1990s

by the Moving Picture Experts Group, that includes video, audio, and interactivity.

MPEG-4 video is designed for interactive multimedia across networks, and works

well for web and wireless streaming video.

CBR -- Acronym for Constant Bit Rate. A compression scheme in which each unit

of input material is always compressed to the same output size. For MPEG-2 video,

for example, this means that the compressed data always has the same data rate (that

is, bytes per second), even when the input material is very easy to encode. See also

VBR.

VBR -- Acronym for Variable Bit Rate. A compression scheme in which each

unit of input material can be compressed to different sizes. For MPEG-2 video, for

example, this means that "easier" sequences (that is, with no motion) can compress to

very small sizes, whereas "hard" sequences (with lots of motion and scene cuts) can

compress to much larger sizes. VBR compression can take better advantage of the

overall available bandwidth of a video transmission or DVD player by allocating the

available bits intelligently to the difficult parts of a sequence. See also CBR.

HDV -- HD on DV - MPEG-2 video in HD resolution

AVCHD -- MPEG-4 AVC in HD

Digital Still Image Formats

BMP -- The standard Windows bitmap still image file format. Bitmap files are not

compressed, and are therefore significantly larger than the same image stored in

formats such as GIF and JPEG.

GIF -- Acronym for Graphics Interchange Format. A still image file format

commonly used on web pages for simple illustrations and animations. Use the JPEG

format for photographic images.

JPEG -- A still image file format developed by the Joint Photographic Experts

Group that can compress photographic images into much smaller file sizes while

sacrificing only a little image quality. Commonly used for photographs on web pages

and in e-mail. See also GIF.

PICT -- The standard Apple Macintosh still image Picture file format.

TIFF -- A lossless image file format designed for photographic images that

compresses the image size while preserving all the image quality. The resulting files

are therefore larger than those with JPEG compression, which sacrifices some detail

in order to significantly reduce the image size.

Digital Audio Formats

AIFF -- Acronym for Audio Interchange File Format; Macintosh audio file format.

Can be used for uncompressed and compressed data. See also WAV.

MP3 -- An audio file format, especially popular for downloading songs from the

web and for storing music in and portable music players. Named for Moving Picture

Experts Group (MPEG) 1, Layer 3. Uses lossy compression to significantly reduce

file size, but often with little perceptible loss in sound quality. Used to store large

song collections on hard disc, download audio to portable audio players, and save

multiple hours of music to CD. Some consumer audio players and set-top DVD

players can play MP3 audio files stored on CD-R/RW discs. See also WAV, Windows

Media Audio.

WAV -- The uncompressed Wave audio file format used with Microsoft Windows.

See also AIFF, MP3, WAV, Windows Media Audio.

Windows Media Audio (WMA) -- The Microsoft Windows Media native audio file

format. Used for compressing, storing, and organizing CDs and downloaded audio

in albums on disk. Also used to download audio to portable audio players. Some

consumer audio players and set-top DVD players can play WMA audio files stored on

CD-R/RW discs. See also MP3, WAV, Windows Media.

Digital Data Rates

Bandwidth -- The amount and rate of data that can be processed or transmitted by a

given device. An analog modem has very little bandwidth compared to a high-speed

cable modem, for instance, so the former cannot download video from the Internet

nearly as quickly as the latter. See also data rate.

Data rate -- The speed at which data is transferred, as in bytes per second. Also called

bit rate. For example, the speed to download or stream a video file over the Internet,

or the speed at which the file must play from a hard disk. When you create a video

or audio file, you can specify the target bit rate at which the file will be played. Also

called bit rate. See also bandwidth.

Bitstream -- A collection of data, as in video or audio data compressed to a file or

transmitted between devices.

Bit -- A binary digit. The fundamental element of computer logic and numbers.

Represents one of two values: zero or one, off or on, false or true. See also byte.

Byte -- A data element containing eight bits, or 256 distinct values. Commonly used

to store a single text character. Computer data transfer rates are traditionally measured

in bits, as in Mb for Megabits (millions of bits, with a lower-case "b"); whereas

computer data storage is traditionally measured in bytes, as in MB, for megabytes

(millions of bytes, with an upper-case "B"). See also bit, GB, KB, MB.

MB -- Megabytes ( millions of bytes). In computer use, a megabyte actually

represents the closest binary power of 2 to a million, or 1024 squared. See also byte,

GB, KB.

GB -- Gigabytes (billions of bytes). In computer use, a gigabyte actually represents

the closest binary power of 2 to a billion, or 1024 cubed. In general use in advertising

DVD disc capacity, however, the number of "GB" is actually used to specify a

different value, a billion decimal. See also byte, KB, MB.

Video Editing Fundamentals

Rough cut -- A quick assembly of raw clips to approximate the desired final program.

As a first step in editing, arranging a collection of clips in the desired order as a

storyboard of the production.

Storyboard -- In video production, a series of cartoonlike panels drawn to describe

a movie, shot by shot. In video editing, an interface that allows you to organize the

sequential flow of your production by arranging thumbnails of each video clip. See

also Timeline.

Scene -- A single video sequence, typically shot in one continuous take. For editing

purposes, it is useful to capture or trim your video material so that each scene is stored

as an individual clip that can then be edited on the Timeline. See also clip.

Clip -- A short piece of video and/or audio, often containing an individual scene.

When creating a video project, you import clip files into bins in your project, and

often trim longer clips into individual scenes. You then edit the clips together on

the Timeline to play in sequential order to tell the "story" of your production, with

transitions between clips and other added effects.

Channel -- The subcomponents of a clip. For images, an alpha channel can contain a

matte or mask image to key certain regions of the image to be transparent. For audio,

the separate left and right channels of a stereo clip.

Timeline -- In video editing, an interface that allows you to assemble a collection of

clips into a production with multiple overlapping tracks. A timeline provides a view

of multiple sources being combined over time, with separate tracks for video, audio,

and superimposed video, as well as transitions and effects. See also storyboard.

Track -- A sequence of video or audio clips in the a video editing timeline that are to

be combined and superimposed into a final production.

Time ruler -- The time display row along the top of the Timeline, showing the time

code along the production. See also edit line.

Edit line -- The current editing point in the Timeline, as displayed in the Monitor

window and used for inserts and deletes. Often shown by a triangle control in the time

ruler with a vertical line down through the Timeline tracks.

Jog -- To move slowly through a program, as with frame advance or frame reverse

VCR controls. Use the jog tread to step frame by frame through a clip or program to

position to a specific frame. See also shuttle.

Shuttle -- To move rapidly through a program, as with scan forward or scan reverse

VCR controls. Use the shuttle slider control to scan rapidly through a clip or program

to move to a general area in the material. See also jog.

Preview -- To play a program on the Timeline and view the appearance of the final

production, including transitions and effects. See also scrub.

Real-time preview -- To play back a program in the Timeline at full rate, while

showing edits such as transitions, effects, overlays, and titles. Allows viewing the

effects of edits immediately, without the need to wait and render the program each

time. Video editors simulate the frame rate and appearance of the final program as

possible depending on the complexity of the program and the system performance.

Scrub -- To play a program in the Timeline by dragging the edit line. You can also

render-scrub to show the visual effects of transitions or other effects, but not at full

playback speed. See also real-time preview.

render -- To generate a video production in its final form, including transitions,

effects, and superimposed tracks. You can render portions of a Timeline in order to

preview your edits at that point, or render the entire production before exporting it in

its final form, to a disk file or out to tape.

Render-scrub -- To preview a program in the Timeline and display the visual effects

of transitions or other effects but not at full playback speed. Used to preview a portion

of the Timeline before rendering it. See also scrub, real-time preview.

Export -- To save your production to a file or to an external video device. You can

export both individual clips and entire productions on the Timeline to a variety of disk

and Web media file formats. See also import.

Scratch disk -- A dedicated work area on hard disk. Used for temporary storage and

for saving preview files.

Preview file -- Temporary file to save the results of rendering a portion of the

Timeline. With these files, editors can preview the results of your editing on the

Timeline at full playback rate, including transitions and effects. See also scratch disk.

Video Editing - User Interface

Project window -- The main window, used to import and save clips used in the

program you are editing and organize them into bins. You save each editing activity

in a separate Project file, including the imported material and editing context.

Bin window -- A window used to import and organize folders of source clips.

Clip window -- A window used to view and trim individual clips. See also Monitor

window, Source view.

Storyboard window -- A window used to organize a group of clips into a sequence.

You can use this window to quickly lay out the scenes to include in your production

into a rough cut and then move them into the Timeline for further editing. See also

Timeline window.

Timeline window -- A window used to assemble, trim, arrange, and superimpose

video, audio, and image clips into a program. See also Storyboard window.

Monitor window -- The used to preview and edit the Source view of individual video

clips and the Program view of the material being assembled on the Timeline. See

also Clip window.

Source view -- The Monitor window view that displays a source clip for viewing

and editing on the Timeline. The source clip can be from a bin in the Project window,

or from a track on the Timeline. See also Program view.

Program view -- The Monitor window view that displays the production being

assembled on the Timeline. Depending on the current settings, this can be a simple

preview of the cuts between adjacent clips, or a fully rendered preview with

transitions and effects. See also Source view.

Movie Capture window -- The window used to preview and record from DV and

analog video and audio devices. Also used for batch capture of a group of clips.

Title window -- A window used to lay out and design title text and graphics.

palette windows -- Small floating windows that provide convenient access to

information, options, and commands used in video editing. Palettes can be adjusted,

hidden, and docked as desired to accommodate your editing style.

Transitions palette -- A window that lists the available video transitions, grouped by

type. Used to access transitions to be applied to the Timeline. You can also reorganize

and customize the list.

Video Effects palette -- A window that lists the available video effects, grouped by

type. Used to access effects to be applied to a video clip. You can also reorganize and

customize the list.

Effect Controls palette -- A window that lists the current effects applied to an audio

or video clip. Used to adjust the order of effects and change effect settings.

Audio Effects palette -- A window that lists the available audio effects, grouped by

type. Used to access effects to be applied to an audio clip. You can also reorganize

and customize the list.

Audio Mixer window -- A window used to dynamically monitor and control the

volume level and pan/balance of multiple audio tracks on the Timeline to combine

them into a final program.

Navigator palette -- A window that displays a miniature view of the current Timeline

work area within the overall program. Used to scroll and zoom the program in the

Timeline view.

Commands palette -- A window that contains a list of preset commands. You can

customize the palette to define buttons and function keys for fast access to often-used

commands.

Info palette -- A window that displays information about a selected clip or transition.

History palette -- A window that displays a list of your recent actions during the

current working session. Used to undo recent operations and return to a previous state

of the project.

Video Editing - Import and Capture

import -- To bring media elements into your current working space. Video editors

can import video and audio clips, still images, and animated sequences in a variety of

formats. You can import both individual clips and folders of clips, and add them to

bins in an open Project. See also capture, export.

capture -- To digitize, or import and convert, video and/or audio into digital format

on your computer from external devices, such as a camcorder or VCR. You typically

use a special video capture card to input analog video into your computer, and then

convert and save it into digital files on your disk. With DV camcorders, you transfer

digital data directly into your computer over a FireWire / 1394 interface. See also

import.

batch capture -- The automated process of capturing an entire group of clips (such as

from a DV camcorder) as defined by a batch list.

batch list -- A list of clips with the timecode values for each In and Out point (also

called a timecode log) to be used in a batch capture process. See also batch capture,

log, timecode.

log -- A list of clips in a longer sequence, identified by starting and ending timecodes.

Use the batch log to build a list of clips to be batch captured from a tape.

Video Editing - Clips and Tracks

single-track editing -- A style of editing in which the Timeline is condensed to a

single row per track. See also A/B editing.

A/B editing -- A style of video editing in which you edit together clips in pairs -

A and B - typically with a transition from one to the next. This style is useful for

assembling a program with simple drag-and-drop convenience. See also single-track

editing.

duration -- A length of time. For a clip, the length of time that it will play,

determined by its overall length. Or if the clip has been trimmed, the difference in

time between its In point and Out point. See also timecode.

crop -- To make an image physically smaller by trimming away one or more edges.

This reduces the dimensions of the image, and reduces the size of the computer file.

trim -- To cut out a segment of a clip by removing frames from the beginning and/

or end. To adjust the In or Out points of a clip to identify the portion to be used in the

final production.

marker -- A placeholder used to mark a specific timecode in a sequence. Use to keep

track of changes, events, or synchronization points in a longer sequence. You can use

the In and Out point markers to mark a clip to be captured from a source tape, to mark

part of a clip to be trimmed, or to mark a portion of the Timeline to be played. See

also In Point, Out Point.

In point -- A placeholder used to mark a specific timecode as the starting point of

a segment in a longer sequence. You can use In and Out points to mark a clip to be

captured from a source tape, to mark part of a clip to be trimmed, or to mark a portion

of the Timeline to be played. See also marker, Out point.

Out point -- A placeholder used to mark a specific timecode as the end point of a

segment in a longer sequence. You can use In and Out points to mark a clip to be

captured from a source tape, to mark part of a clip to be trimmed, or to mark a portion

of the Timeline to be played. See also marker, In point.

split edit -- To adjust the video and audio portions of a clip separately so that they

start or end at different times. Used for audio cross-fading so that the audio can lead

in or fade out independently from the cut in the video. See also L-cut and J-cut.

J-cut -- A split edit in which the In point of a clip is adjusted to overlap the preceding

clip so that the audio portion of the later clip starts playing before its video as a lead-

in to the visual cut. Also called an audio lead. See also L-cut.

L-cut -- A split edit in which the audio Out point of a clip is extended beyond the

video Out point, so that the audio cuts after the video and continues playing over the

beginning of the next clip. See also J-cut.

four-point edit -- A method of setting In and Out points to precisely control where

and how frames are inserted into a Timeline. In a four-point edit, you set all four In

and Out markers, and the editor displays a warning dialog if the durations do not

match. See also three-point edit.

three-point edit -- A method of setting In and Out points to precisely control where

and how frames are inserted into a Timeline. In a three-point edit, you set any three

such markers, and the software determines the fourth to match the specified duration.

See also four-point edit.

ripple edit -- A method of editing in the Timeline so that when new material is

inserted, or existing material is deleted, other material is adjusted to fit. In a ripple

edit, the change ripples through the rest of the material, as the existing clips slide

apart to make room for the new material, or slide together to fill a gap. See also

rolling edit, slide edit, slip edit.

rolling edit -- A method of editing in the Timeline by adjusting and trimming two

adjacent clips. When you roll the cut point between the adjacent clips, the durations of

the two clips are adjusted to keep the overall program duration unchanged. The Out

point of the first clip is changed in tandem with the In point of the second clip so

that, as one increases in duration, the other decreases to match it. See also ripple edit,

slide edit, slip edit.

slide edit -- A method of editing in the Timeline by moving a clip and trimming

neighboring clips to adjust to the change. When you slide a clip earlier or later in the

program, the neighboring clips are trimmed accordingly by changing their In and

Out points so that the duration of the overall program remains unchanged. See also

ripple edit, rolling edit, slip edit.

slip edit -- A method of editing in the Timeline by changing the trim points in a

clip. When you slip the trim points earlier or later in a clip, the In and Out points

are adjusted correspondingly so that the duration of the clip is unchanged. A slip

edit also does not affect the rest of the program on the Timeline. See also ripple edit,

rolling edit, slip edit.

Video Editing - Titles

title -- Onscreen text (and associated graphics) that can be used to add information

to your production. Used as a title screen at the beginning of your production, for

subtitles superimposed under the video, and for rolling credits at the end.

subtitle -- A text overlay on video materials, typically used to display the audio

dialog in various languages, or to transcribe hard-to-understand speech.

caption -- Title text that labels a scene or identifies a location or person onscreen.

credit -- Title text that identifies the people who contributed to a production. Usually

scrolled at the end of a show.

crawl -- To scroll a line of title text sideways, left or right across the screen. See also

roll.

roll -- To scroll lines of title text vertically up or down the screen. See also crawl.

kerning -- The spacing between adjacent characters in a text string, as in a title.

Video Editing - Transitions

transition -- A visual effect to segue from the end of one clip or scene and the start

of the next. The most basic transition is a cut, in which the last frame of one clip is

immediately followed by the first frame of the next clip. More interesting transition

effects include fades, dissolves, and wipes between adjacent clips.

cut -- To switch instantly from one clip to another. A video cut appears suddenly

onscreen without any other kind of transition effect. The cut is the most basic kind

of transition for changing scenes and dropping titles onto the screen. See also fade,

transition.

fade -- A gradual transition from one clip to another. With video, the clip changes

from transparent to fully opaque (or vice versa) to fade in or out. With audio, the gain

changes between silence and full volume.

dissolve -- A video transition in which one video clip fades into the next. See also

fade, transition.

wipe -- A video transition in which the new video physically moves into the frame

while displacing the old video.

Video Editing - Effects

effect -- The result of processing audio and video clips to enhance, improve, or distort

them. See also filter.

animate -- To move and manipulate an object over time, such as a title, a

superimposed logo, or a transition between frames.

keyframe -- A point along a timeline or path that defines where and how the

settings for an effect will change. One or more settings can then be interpolated from

keyframe to keyframe to create the appearance of a smoothly change over a series of

frames or along a motion path. See also interpolate.

scale -- To reduce or enlarge an image or video sequence by squeezing or stretching

the entire image to a smaller or larger image resolution.

filter -- A transformation applied to a video or audio clip to enhance it or create a

visual or auditory effect. See also effect.

gamma -- A display setting related to the brightness of the middle tones of an image.

You can adjust the gamma of an image to lighten or darken the midtones (the middle-

gray levels), without significantly changing the dark and light areas (the shadows and

highlights).

gradient -- Gradual change from one color (or intensity level) to another. Gradient

colors can also become opaque or transparent, varying in translucency from one side

to the other.

interpolate -- To automatically create graduated steps between two or more

keyframes to create smooth transitions for video, audio, and motion effects.

antialias -- To smooth out a jagged or stair-step appearance or motion between

adjacent points so that it appears continuous.

motion blur -- The effect of tracking a speeding object and thus blurring the

background because of the motion.

Video Editing - Compositing

composite - superimpose -- To layer multiple tracks onto the Timeline. To

composite portions of multiple clips into the final production by overlaying clips with

transparent regions to allow the underlying tracks to show through. See also key.

superimpose track -- In video editing, the Video 2 track and above, which can

include titles, logos, and other material to be overlaid on the bottom Video 1 track.

opaque -- Regions of a superimposed image that are solid (not transparent), and

therefore cover over the underlying image. See also transparent.

transparent -- Regions of a superimposed image that are invisible, and therefore

show through to the underlying image, as used for logo overlays and blue-screen

effects. May be defined using a key color or alpha mask. Technically, overlays also

can be translucent, and blend portions of the two images. See also opaque.

key -- To specify a region of an image or video clip to be used as a mask for

transparency. Used to make part of the scene transparent or semitransparent, and

then composite it with other superimposed images or video tracks. The region can

be specified using features such as color (a color key) or intensity, or with a separate

alpha mask or image matte. See also blue screen, matte.

mask - An image which defines areas in a frame to be used as a transparency key or

matte. Each pixel in the mask image indicates the degree of transparency to be used

for the corresponding pixel position in each frame. See key, matte.

matte -- An image mask used to define the transparent areas of each frame to be used

in superimposing multiple clips. See also key.

alpha channel -- Extra information stored with an image to define transparent areas

used for keying and superimpositions. Also called an alpha mask. Sometimes present

in files prepared using a tool such as Adobe Photoshop or Illustrator. See also key.

blue screen -- A specially colored backdrop (typically blue or green) that can be

matched with a color key and made transparent so that it can be replaced with another

video layer. For example, you can cut out a subject from the blue screen background

and composite it into another scene. See also matte, key.

garbage matte -- A mask used in a keying operation to remove a region of a frame

that contains unwanted objects.

watermark -- A small, semitransparent graphic that identifies a scene or speaker.

Many TV broadcasts use a watermark to let you know what channel you're watching.

Audio Editing and Effects

rip -- To extract data from a removable disc. Typically, to copy songs from a

prerecorded CD-Audio disc to hard disc in order to organize a collection, and play

and burn personalized playlists.

playlist -- Typically, a list of songs to be played in a specified order. Used to organize

collections to download to a portable audio player or burn to a CD.

sweeten -- To use audio effects to enhance and manipulate the audio sound.

audio waveform -- A graphical representation of an audio clip, helping to visualize

the sound in the clip by showing the signal levels. Editors can show a waveform in

audio tracks in the Timeline and in a separate Clip window when you open an audio

clip.

gang -- To adjust multiple tracks at the same time, as in the Audio Mixer window.

VU meter -- An audio mixer's display of audio levels for each track.

gain -- Overall audio output volume. Increase gain to amplify a clip, or decrease gain

to attenuate a clip, making it quieter.

amplify -- Increase the audio volume.

attenuate -- To reduce audio strength or volume.

dynamic range -- The difference between the softest and loudest sounds. Decrease to

compress the range and reduce noise, or expand to emphasize volume differences.

balance -- To distribute two channels of a stereo clip between the left and right

channels. See also pan.

pan -- To move the apparent location of a mono audio track to position it between the

left and right stereo channels. With stereo clips, you adjust the balance between the

two channels. See also balance.

cross-fade -- See fade.

delay -- An audio effect that provides an echo of a sound after a specified time period.

equalize -- To adjust the tonal quality of an audio clip. As with graphic equalizers

found in home or auto audio equipment, an equalize effect can to boost or cut the

original signal at different frequency bands.

reverb -- An audio effect that simulates the ambience of a room of a specific size and

with different sound-absorbent properties.

bandpass effects -- Audio effects designed to remove specific frequencies from an

audio clip (manifested as hisses, whines, and hums).