Type Property


The subtitle track containing forced and non-forced subtitles is associated with a subtitle track containing only forced subtitles.


static let forcedSubtitlesOnly: AVAssetTrack.AssociationType


Non-forced subtitles usually transcribe all “normal” dialogue in a media asset and are typically not presented by default. Forced subtitles are those that are essential for presentation even when normal subtitles are disabled (for example, when a character speaks in a language foreign to that of the audio track).

Both subtitle tracks are expected to present forced subtitles with the same content and the same language, but may have different timing.

See Also

Track Association Types

static let audioFallback: AVAssetTrack.AssociationType

The track contains the same content as another track, but in a more widely supported format.

static let chapterList: AVAssetTrack.AssociationType

The associated track contains chapter information for the base track.

static let metadataReferent: AVAssetTrack.AssociationType

The metadata track is associated with the track being described or annotated.

static let selectionFollower: AVAssetTrack.AssociationType

The second track in the association is considered an appropriate default for the first track.

static let timecode: AVAssetTrack.AssociationType

The track is associated with a timecode track containing timing information for the original track.