(^556) PC Hardware: A Beginner’s Guide
unavailable, drivers can often be found on the manufacturer’s Web site. Frequently a man-
ufacturer will release updated drivers that include features or bug fixes not found on the
original installation disk, so it is always good practice to check the Web site for updates.
Video and Graphic Files
It is not likely that you would videotape a birthday party with the camera’s sound turned
off. Full-motion video images are rarely recorded without sound because the result
would lack meaning and context. This is why the majority of the multimedia architec-
turesusedtostoreandtransfervideoimagesonthePCarethesameasthosethatareused
to store audio data. Combining video images with sound and storing them in the same
file requires more sophisticated file formats and compression algorithms than are re-
quired just for audio data. Of course, the major drawback of combining audio with video
is that it results in larger, more complex files.
The three more popular video file formats are AVI, MPEG, and QuickTime (MOV).AVI
AVI (audio/visual interleaved), which is also called Video for Windows and ActiveMovie,
is Microsoft’s proprietary digital audio-visual architecture. It is actually more of an inter-
face to a set of Windows graphic display routines than it is a video file format. Nonetheless,
AVI files produce good video and sound reproduction.
Its drawbacks include the smaller window sizes used for playback and the larger file
sizes it can generate. For example, a 30-second AVI file requires about 1.4MB of disk stor-
age space. AVI is no longer supported by Microsoft and is being replaced by
DirectShow/ActiveMovie, which supports playback of multimedia from the Web,
CD-ROM, and DVD.MPEG
MPEG (Moving Picture Experts Group) is a nonproprietary, digital audio-visual architec-
ture, developed by the same organization that created the JPEG standard (on which MPEG
is based). MPEG was born from the desire for full-motion video on personal computers; us-
ing MPEG, computer filmmakers have the ability to create a full-screen, full-motion video
with a frame rate of 30 frames per second, the same frame rate used in television.
The size of the MPEG file depends upon the amount of compression used. Because it
is a derivation of the JPEG standard, MPEG is a very popular compression method for
video data files. Like its cousin JPEG, however, higher compression rates usually result in
poorer image quality.