Apple Compressor 2 - Manual (Page 98)

98 Chapter 7 Creating Dolby Digital Professional Output Files
Preprocessing Tab Settings
Preprocessing options are applied to the audio data before encoding. With the
exception of the Compression Preset setting, leave these settings at their default values
unless you have a specific technical reason for changing them.
 Compression Preset: Specifies one of the dynamic range processing modes built in to
the AC-3 format. The default of Film Standard Compression should only be used
when you are encoding an original mix intended for cinema. In almost all cases, you
should choose None.