Specifications
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A Digital Video Primer
Fields: e sets of upper (odd) and lower (even) lines drawn by the electron gun when illuminating the
phosphors on the inside of a standard television screen, thereby resulting in displaying an interlaced
image. In the NTSC standard, one eld contains 262.5 lines; two elds make up a complete television
frame. e lines of eld 1 are vertically interlaced with eld 2 to produce 525 lines of resolution.
Final cut: e nal video production, assembled from high-quality clips, and ready for export to
the selected delivery media.
FireWire: e Apple Computer trade name for IEEE 1394.
Four-point edit: An edit used for replacing footage in a program when the precise In and Out
points of the clip to be inserted and the portion of the program to be replaced are critical and
are, therefore, specied by the editor. e four-point editing feature in Adobe Premiere Pro alerts
the editor to any discrepancy in the two clips and automatically suggests alternatives.
fps: Frames per second, the measurement of frame rate.
Frame: A single still image in a sequence of images which, when displayed in rapid succession, creates
the illusion of motion. e more frames per second (fps), the smoother the motion appears.
Frame rate: e number of video frames displayed per second (fps). In interlaced scanning, a
complete frame consisting of two elds. Video formatted using the NTSC standard has a frame
rate of 29.97 fps. PAL and SECAM standards use a frame rate of 25 fps.
Fullscreen: Format that utilizes the entire aspect ratio of a standard (4:3) television screen.
Generation loss: Incremental reduction in image or sound quality caused when analog audio or video
is copied, and then the copy is copied, and so on. Generation loss does not occur when copying digital
media unless the media is repeatedly processed or compressed and decompressed.
Handles: Extra frames specied before the In and Out points of a clip that may be needed to
accommodate transitions or editing adjustments.
Headroom: e practice of capturing digital media at a higher quality setting than will be used
in the nal product in order to preserve quality through editing and processing. In audio, extra
audio gain above the average level to help prevent peak levels from distorting.
Horizontal resolution: e number of pixels across each horizontal scan line on a television.
IEEE 1394: e interface standard that enables the direct transfer of DV between devices such as a DV
camcorder and computer; also used to describe the cables and connectors utilizing this standard.
i.LINK: e Sony trade name for IEEE 1394.
In point: e point in a source clip at which the material used in a video program begins.
Insert edit: An edit in which a series of frames is added, lengthening the duration of the overall
program.
Interframe compression: Reduces the amount of video information by storing only the dierences
between a frame and those that precede and follow it. (Also known as temporal compression.)
Interlacing: System developed for early television and still in use in standard television displays.
To compensate for limited persistence, the electron gun used to illuminate the phosphors coating
the inside of the screen alternately draws even, then odd horizontal lines. By the time the even
lines are dimming, the odd lines are illuminated. We perceive these interlaced elds of lines as
complete pictures.
Intraframe compression: Reduces the amount of video information within each frame. (Also
known as spatial compression.)
J-cut: A type of split edit where the audio In point is earlier than the video In point so that the
audio begins to be heard during the previous video clip. Also known as an audio lead.
JPEG: File format dened by the Joint Photographic Experts Group of the International Orga-
nization for Standardization (ISO) that sets a standard for compressing still computer images.
Because video is a sequence of still computer images played one aer another, JPEG compression
can be used to compress video (see MJPEG).