Additional information
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En
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 (standard) 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
1
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.
Dolby Pro Logic / Pro Logic II
A matrix decoding system that extracts 4.1
(Dolby Pro Logic) or 5.1 (Dolby Pro Logic II)
channel surround sound from a two channel
source.
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 System. 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 manufacturers use this compressed
file format which carries date, time and
thumbnail information, as well as the picture
data.
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