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46 • Configuring the Dolby Encoders BAP User Guide (v1.0)
To configure the preprocessing engine for the Dolby encoder channel
1. Select the Preprocessing tab.
2. Use the Line Mode Profile menu if your downstream equipment requires a specific type of
speaker-level output. This is set to Film Standard by default.
3. Use the RF Mode Profile menu if you require a downmixed signal for subsequent channel 3 RF
modulation and transmission. This is set to Film Standard by default.
4. Select the Phase Shift box to apply a 90° phase shift to the surround channels.
 Select this box if a surround-compatible downmix is later applied to the decoded audio and you
want to avoid the possibility of the input signals in the L and Ls channels canceling each other
out.
5. Select the 3dB Sound Attenuation box to apply a 3dB attenuation to the surround channels.
Specifying the Preferred Stereo Downmix Mode
The BAP enables you to specify the preferred stereo downmix mode when a stereo-compatible
Dolby Surround downmix of a multichannel source program for decoding. This feature allows the
user to specify how the program should be downmixed by the downstream decoder device. The
device then downmixes the tracks to a stereo track as specified by the preferred mode.
To specify the preferred stereo downmix mode
1. Select the Downmixing tab.
2. Use the Preferred Stereo Downmix Mode menu to choose one of the following:
• Lt/Rt — sums the Surround channels and adds them, in-phase to the Left channel and
out-of-phase to the Right channel. This allows a Dolby Surround Pro Logic decoder to
reconstruct the Lt/Rt (Left total/Right total) channels for a Pro Logic setup.
• Lo/Ro — adds the Left and Right Surround channels discretely to the Left and Right speaker
channels, respectively. This preserves the stereo separation for stereo-only monitoring and
produces a mono-compatible signal (Left only/Right only).
• Pro Logic II Downmix — processes the stereo source into 5 channels (Right Front, Center,
Left Front, Right Back, and Left Back). Also enables the processing of 5-channels from a
4-channel Dolby Stereo source.
3. Use the provided Mix Level fields to apply a level shift value to the specified channel when
downmixing.
Loudness
If you choose to disable the Dolby RTLL for an output path, you have the option in the encoder
interface to adjust the loudness level as required.
To configure the loudness level
1. Select the Loudness tab.
2. Use the Fallback Dialnorm slider to report the output loudness level to the downstream
decoder.