MPTF/MPTF Discussions/Timed Text

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Submitter: CableLabs

Tracker Issue ID: ISSUE-33


The content provider is able to identify temporal regions for display of textual data with the video playback. Two important applications of timed text are:

  1. Closed captions
  2. Subtitles


  1. Need textual information for hearing-impaired viewers or speakers of different languages.


  1. Closed captioning information may need to be transmitted using existing government-mandated television standards.
  2. Accessibility for different language speakers is desirable.

What needs to be standardized

Timed text tracks currently support track kinds of caption and subtitle

  1. Track elements are expected to only appear at the beginning of a media stream. Track elements will come and go if the media stream is scheduled programming to there needs to be way to account for this.