WebVTT is a widely used text format for timed subtitles and captions, carried as a separate track referenced from the manifest and rendered by the player in sync with the video. It supports basic positioning and styling and is the common choice for web and many device players.
It sits in a small family of caption formats - alongside TTML and the broadcast-grade IMSC - and platforms often convert between them per device. Beyond translation subtitles, this track type carries closed captions for accessibility, which are legally required in many markets, making correct caption handling a compliance issue, not just a feature.
