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data rate The speed at which data can be transferred, often described in megabytes
per second (MB/sec.) or megabits per second (Mbps). The higher a video le’s data
rate, the higher quality it is, but the more system resources (processor speed, hard disk
space, and performance) it requires. Some codecs allow you to specify a maximum
data rate for a movie during capture.
decibel (dB) Unit of measurement for sound levels; a logarithmic scale used to
describe the loudness of sound as perceived by the human ear. (1 dB corresponds to
approximately the smallest volume change that the average human ear can perceive.)
For digital audio, dBFS is the standard decibel unit of sound level measurement.
Disk Utility Disk Utility is an Apple program that performs disk-related tasks in
Mac OS X. It’s located in the Utilities folder inside the Applications folder. For more
information, see Mac Help.
distributed processing Using Compressor, you can congure one or more computers
to perform a portion of the render processing when sharing your project. Depending
on your network and the nature of your project, distributed processing can greatly
speed up the processing.
downmixing The process used to combine multiple audio channels into a single
stereo (or dual mono) pair. Also referred to as mixing down.
drop frame timecode NTSC timecode that skips ahead in time by two frame numbers
each minute, except every tenth minute, so that the timecode agrees with the actual
elapsed clock time. (Timecode numbers are skipped, but actual video frames are not
skipped.) This skipping corrects for NTSC’s actual frame rate of 29.97 fps, which causes
non-drop frame timecode to lag behind actual elapsed time by 3 seconds and 18
frames per hour. To avoid confusion, drop frame timecode should be avoided in lm-
based productions. See also non-drop frame timecode.
drop shadow An eect that creates an articial shadow behind an image. Typically
used with graphics and text.
DV A standard-denition (SD) digital videotape recorder format that records an 8-bit,
5:1 compressed component video signal with 4:1:1 color sampling (PAL uses 4:2:0).
Supports two tracks of audio with 16-bit, 48 kHz audio sampling, or four tracks of audio
with 12-bit, 32 kHz audio sampling.
DVCAM A standard-denition (SD) digital videotape recorder format that records an
8-bit, 5:1 compressed component video signal with 4:1:1 color sampling (PAL uses
4:2:0). Supports two tracks of audio with 16-bit, 48 kHz audio sampling, or four tracks of
audio with 12-bit, 32 kHz audio sampling.
538 Chapter 18 Glossary