Additional information
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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
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.
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.
File extension
A tag added to the end of a filename to
indicate the type of file. For example, “.mp3”
indicates an MP3 file.
MP3
MP3 (MPEG1 audio layer 3) is a compressed
audio file format. Files are recognized by
their file extension “.mp3” or “.MP3”.
MPEG audio
An audio format used on Video CDs and
some DVD discs. This unit can convert
MPEG audio to PCM format for wider
compatibility with digital recorders and AV
amplifiers. See also
PCM
.
MPEG video
The video format used for Video CDs and
DVDs. Video CD uses the older MPEG-1
standard, while DVD uses the newer and
much better quality MPEG-2 standard.
PCM (Pulse Code Modulation)
The most common system of encoding
digital audio, found on CDs and DAT.
Excellent quality, but requires a lot of data
compared to formats such as Dolby Digital
and MPEG audio. See also
Digital audio
.
PBC (PlayBack Control) (Video CD only)
A system of navigating a Video CD through
on-screen menus recorded onto the disc.
Especially good for discs that you would
normally not watch from beginning to end all
at once—karaoke discs, for example.
