The option includes content marked by the content author as secondary to the presentation of the asset.
- iOS 5.0+
- macOS 10.8+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 2.0+
Example: an option that presents audio media containing commentary on the presentation would typically have this characteristic.
The value of this characteristic is
For QuickTime movie and .m4v files, a media option is considered to have the characteristic
is if it’s explicitly tagged with that characteristic or if, as a member of an alternate track group, its associated track is excluded from autoselection.