Interaction between Bypass mode setting in OS and Primary Audio Only
The option in Advanced Audio Settings will only be available if the system is equipped with S/PDIF or HDMI port.
The setting only works when Bypass mode is enabled during digital audio out. Once the option is enabled, WinDVD will output primary audio when producing digital output. If the option is disabled, WinDVD will enable the mixer and produce mixed audio.
This option is enabled by default in BD-ROM discs.