Timed Text Markup Language represents text associated with timing information and can describe styling or layout for supported workflows. It is used in subtitle and caption exchange or distribution arrangements. A TTML document is not the video itself, and practical playback depends on a system supporting the particular form and features present in the resource.
A practical example
A caption workflow can carry timed dialogue and presentation information in a TTML document while storing programme video separately. A compatible player or distribution system combines the timing information with media playback so the intended text appears with the programme.
A common misunderstanding
A file being valid XML does not mean that a player understands its timed-text vocabulary or profile. Check the supported subtitle arrangement rather than treating all XML-based resources as interchangeable.
Related terms
Further reading
Stable technical definition. Editorial approach