Additional information10
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Glossary
Analog audio
An electrical signal that directly represents
sound. Compare this to digital audio which
can be an electrical signal, but is an indirect
representation of sound. See also Digital
audio.
Aspect ratio
The width of a TV screen relative to its height.
Conventional TVs are 4:3 (in other words, the
screen is almost square); widescreen models
are 16:9 (the screen is almost twice as wide as
it is high).
Digital audio
An indirect representation of sound by
numbers. During recording, the sound is
measured at discrete intervals (44,100 times a
second for CD audio) by an analog-to-digital
converter, generating a stream of numbers.
On playback, a digital-to-analog converter
generates an analog signal based on these
numbers. See also Sampling frequency and
Analog audio.
Dolby Digital
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Using a maximum of 5.1 channels of audio,
this high quality surround system is used in
many of the finer movie theaters around the
world.
The on-screen display shows which channels
are active, for example showing 3/2.1. The 3
being the two front channels and the center
channel; the 2 being the surround channels,
and the .1 being the LFE channel.
DRM
DRM (digital rights management) is a type of
server software developed to enable secure
distribution of paid content over the web,
recently incorporated by WMA (Windows
Media Audio ).
DTS
DTS stands for Digital Theater Systems. DTS
is a surround system different from Dolby
Digital that has become a popular surround
sound format for movies.
Dynamic range
The difference between the quietest and
loudest sounds possible in an audio signal
(without distorting or getting lost in noise).
Dolby Digital and DTS soundtracks are
capable of a very wide dynamic range,
delivering dramatic cinema-like effects.
EXIF (Exchangeable Image File)
A file format developed by Fuji Photo Film for
digital still cameras. Digital cameras from
various manuafcturers use this compressed
file format which carries date, time and
thumbnail information, as well as the picture
data.
File extension
A tag added to the end of a filename to
indicate the type of file. For example, “.mp3”
indicates an MP3 file.
ISO 9660 format
This is the international standard for the
format logic of CD-ROM folders and files. For
the ISO9660 format, there are regulations for
the following two levels.
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