User Guide

274 Appendix B, AC-3 Encoding
AC-3 Parameter Settings
The following table describes the AC-3 Parameter Settings, as well as their recommended
settings. The default settings differ depending on the selected Audio Coding Mode.
AC-3 Parameter Settings
Parameter Definition Recommended Setting
Data Rate
(kbps)
Determines the band width for the resulting Dolby
Digital streams, as well how much space they will
occupy on the disc.
64–448 kbps, depending
on the project.
Sample Rate
Determines the sample rate for the resulting Dolby
Digital streams.
48 kHz
Dialog
Normalization
A reference level for gain control on playback. The
decoder uses this value to achieve consistent dialog
level for titles with varying dynamic range.
Depends on material.
Bit Stream
Mode
Determines the type of service for the bitstream. For
DVD discs, Complete Main is the most commonly-
used option. The other settings are used primarily for
HDTV (Broadcast).
Complete Main (for all
modes except Karaoke).
Select Karaoke for titles
that have Karaoke audio.
Center Mix
Level
The volume level of the center channel with respect
to the left and right channels when a 5.1 mix is played
in a stereo environment. Since in this case the Dolby
Digital decoder sends the center channel to both the
left and right speakers, raising the volume of the
channel, the channel’s volume should be attenuated
accordingly.
Depends on project.
Surround Mix
Level
The volume level of the surround channels with
respect to the left and right channels when a surround
mix is played in a stereo environment.
-3 dB for Audio Coding
Modes with a surround
channel (2/1, 2/2, 3/1,
and 3/2).
Dolby
Surround
Mode
Determines whether a two-channel Dolby Digital
stream is Surround encoded. This information is not
used by the Dolby Digital decoding algorithm, but may
be used by other audio reproduction equipment, such
as a Dolby Pro Logic Surround decoder.
If two-channel source
material was Surround
encoded (encoded for
Dolby ProLogic), select
Dolby Surround.
Copyright Bit
Specifies that the material is copyrighted. Depends on the project.