Apple Compressor 3 - Manual (Page 143)

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
• 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.
Important: It is critical that you set the Audio tab’s Dialog Normalization correctly if
you intend to use any of these Compression Preset settings. The Compression Preset
settings assume that the audio, after the dialogue has been normalized, is at the normal
listening level of 31 dBFS. Levels that are consistently louder than that result in distorted
sound and erratic levels.
Note: If you are building a Dolby Digital Professional 5.1-channel surround sound DVD,
then you will use Film Standard Compression.
General
• Apply Digital Deemphasis: Specifies whether input audio data is preemphasized and
needs to be deemphasized before encoding.
143 Chapter 10 Creating Dolby Digital Professional Output Files