User Guide

AC-3 Parameter Settings 275
Original Bit
Stream
Specifies that the material is the original and not a
copy.
On (all modes).
Mix Level
The acoustic sound pressure level of the dialog during
the final audio mixing session.
Depends on the project.
Room Type
The type and calibration of the mixing room used for
the final audio mixing session. The value of Room Type
is not typically used within the Dolby Digital decoding
algorithm, but may be used by other parts of the
audio reproduction equipment.
Depends on the project.
Digital
Deemphasis
If you have emphasized source material, this setting
enables or disables it.
Depends on source
material
DC Highpass
Filter
A DC highpass filter for all input channels. On (for all modes).
Bandwidth
Lowpass Filter
A lowpass filter with a cut-off near the specified audio
bandwidth that is applied to the main input channels.
If the digital signal fed to the main input channels
does not contain information above the specified
audio bandwidth, this filter may be disabled.
If you are compressing a lot of channels at low rates
or if you have a lot of high frequencies in your source
material, it is recommended that you use this filter. It
removes high-frequency material that the encoder
would have removed anyway.
On (for all modes).
LFE Lowpass
Filter
A 120 Hz lowpass filter applied to the LFE channel. On for encodes that
include an LFE channel.
Surround
Channel
90 Phase-Shift
A 90° phase-shift to the surround channels at the
input. This is useful for generating multi-channel Dolby
Digital streams that can be down-mixed in an external
2-channel decoder to create a true Dolby Surround
compatible output.
On for Audio Coding
Modes with a surround
channel (2/1, 2/2, 3/1,
and 3/2).
AC-3 Parameter Settings
Parameter Definition Recommended Setting