Specifications
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A Digital Video Primer
Key: A method for creating transparency, such as a blue-screen key or a chromakey.
Keyframe: A frame that is used as a reference for any of a variety of functions. For example, in
interframe video compression, keyframes typically store complete information about the image,
while the frames in between may store only the ways in which they dier from one or more
keyframes; in video editing, a frame can be designated as a keyframe in order to dene certain
properties of the audio or video at a particular time. Keyframes are typically used by eects pro-
grams or plug-ins to dene properties, like image color or frame position and size, at a number
of points on a timeline in order change the properties over time. For example, keyframes can be
used to dene the movement of elements in an animation.
Keyframing: e process of creating an animated clip by selecting a beginning image and an
ending image whereby the soware automatically generates the frames in between (similar to
tweening).
Keying: e technique of using a key to apply transparency when superimposing video clips.
L-cut: A type of split edit where the audio Out point is later than the video Out point so that the
audio continues to be heard with the next video clip.
Log: A list of shots described with information pertinent to content or other attributes; or the
process of creating such a list.
Lossless: A process that does not result in a loss of signal delity or data; for example, compres-
sion by run-length encoding or the transfer of DV via an IEEE 1394 connection.
Lossy: Generally refers to a compression scheme or other process, such as duplication, that causes
degradation of signal delity and loss of data.
Luminance: Brightness portion of a video signal.
MAM: Media asset management.
Markers: Can be added during editing to indicate important points in the Timeline or in indi-
vidual clips. Markers are for reference only; they do not alter the video program.
Mask: See Matte. e term mask is usually used in working with still images, while the term
matte is typically used in lm and video post-production.
Matte: An image that species an area of another image on which to apply transparency, semi-
transparency, or some other eect.
Matting: e technique of using a matte to specify transparency when superimposing video clips.
Media asset management (MAM): e warehousing of digital media content in such a way that
it can be easily referenced and retrieved using a relational database. Also known as digital asset
management (DAM). Content (images, graphics, animations, video, and audio) is linked to
critical information about that content, known as metadata, which can include creation date, a
description, the equipment (camera or recorder) that recorded the material, timecode, and so
on. Together, the content and the metadata for a single item comprise an asset. One of the most
signicant features and benets of a MAM is that assets can also be linked to other systems, such
as nancial databases.
Metadata: In media asset management formats such as AAF, that portion of the data consisting
of ancillary information such as description, source, and time-code, and so forth.
MJPEG: Motion JPEG.
Motion control photography: A system for using computers to precisely control camera
movement so that multiple shots can be made with matching movement. e shots can then be
composited to appear as one shot.
Motion effect: Speeding up, slowing down, or strobing of video.