Overview: Streaming subtitle transports

Streaming subtitle transports relate timed text to segmented HLS or MPEG-DASH presentations.

A subtitle stream must remain aligned with the presentation's media timeline as segments are selected and delivered. HLS and MPEG-DASH provide their own signaling and transport conventions for that job. Their pages connect cue timing and track selection to the streaming representation received by the player.

  • Subtitles in HLS
    HLS can deliver separately selected WebVTT subtitle renditions whose cue times must be mapped to the shared media timeline.

  • Timed text in MPEG-DASH
    MPEG-DASH describes selectable timed-text representations and maps their sample timelines into periods on the presentation timeline.

References