Appendix E: Glossary 329
image quality is sacrificed. The loss of quality may be
negligible or severe depending on the amount of
compression.
Cropping: Choosing the area of an image to be
displayed.
Data rate: The quantity of data transmitted per unit
time; for example, the number of bytes read from or
written to a hard drive per second, or the amount of
video data processed per second.
Data transfer rate: The measurement of the speed at
which information passes between the storage device
(e.g. CD-ROM or hard drive) and the display device
(e.g. monitor or MCI device). Depending on the
devices used, some transfer rates may offer better
performance than others.
DCT: Discrete Cosine Transformation – part of
JPEG image data compression and related
algorithms. The brightness and color information is
saved as a frequency coefficient.
DirectShow: System extension by Microsoft for
multimedia applications under Windows.
ActiveMovie
DirectMedia: System extension by Microsoft for
multimedia applications under Windows.
ActiveMovie
DirectX: A bundle of several system extensions
developed by Microsoft for Windows 95 and its
successors to make possible video and game
acceleration.
Dissolve: A transitional effect in which the video is
faded from one scene to the next.
