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Bitstream
This is the digital form of multiple channel audio data (e.g. 5.1 channel)
before it is decoded into its various channels.
Chapter
This is the smallest division on DVD and is roughly equivalent to a track.
Decoder
A decoder restores the coded audio signals on DVDs to normal.
This is catled decoding.
Dolby Digital
This is a method of coding digital signals developed by Dolby Laboratories,
Apart from stereo (2-channel) audio, these signals can also be 5.1-channel
audio. A large amount of audio information can be recorded on one disc
using this method,
Dolby Pro Logic
A surround system where a 4-channel audio track is recorded as 2 chan-
nels and then is restored to 4 channels for play. The surround channel is
monaural and can reproduce up to 7 KHz.
DTS (Digital Theater Systems)
This method of coding digital signals was developed by Digital Theater
Systems. The signals are compressed at a low ratio to maintain sound
quality.
Dynamic range
Dynamic range is the difference between the lowest lavel of sound that can
be heard above the noise of the equipment and the highest level of sound
before distortion occurs.
Fletd
One frame is made up of two fields. A regular television shows these fields
one after the other to create frames.
Frame
Frames are the still pictures that go together to make a moving picture.
There are about thirty frames shown each second.
Frame still and field still
A still is shown when you pause a moving picture. A frame still is made up
of two alternating fields, so the picture may appear blurred, but overall qua-
lity is high. A field still is not blurred, but it has only half the information of a
frame still so picture quality is lower,
VP/B
MPEG 2, the video compression standard adapted for use with DVD,
codes frames using these three picture types.
fk Intra coded picture (I-picture)
This is the standard picture and is a complete picture in itself. This
means it has the best picture quality and is the best to use when adjust-
ing the picture.
P: Predictive coded picture (P-picture)
This picture is calculated based on past | and P-pictures.
B: Bidirectionally-predictive coded picture (B-picture)
This picture is calculated by comparing past and future | and P-pictures
so it has the lowest volume of information.
PBC (Playback control)
This method of controlling disc play is included on version 2.0 Video CDs.
You are able to interact with the disc through menus.
PCM (Pulse code modulation), Linear PCM
PCM is the usual digital method used for Audio CDs. DVDs have a greater
volume so they use linear PCM, which has a higher sampling rate.
Sampling rate
This is the number of samples of sound taken per second during conver
sion to a digital signal. Sampling frequency is expressed in kilohertz (kHz).
A high sampling frequency results in a sound close to the original when
played back,
Title
This is the targest division on DVD.
Track
This is the smallest division on Video CD and Audio CD, and usually
equates to a single song.
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