Definition
VideoText editorial team. Updated September 13, 2026.
A caption file is a timed-text document a player can load as a track — commonly SRT, WebVTT, TTML, or SCC. It stores cues, not the video pixels.
The sections below explain how caption file is used in transcription and subtitle work, what people often mix up, and which VideoText workflow applies when the next step is a file or review pass.
Upload the sidecar to YouTube, a streaming packager, or an HTML5 track. Timing repairs and translation work on these files, not on text burned into the picture.
A caption file usually travels beside the video as a separate sidecar — an SRT or VTT the player loads on request. The alternative is embedding the caption data inside the container or, in broadcast, inside the video signal itself.
Sidecar files are easy to edit, replace and translate, which is why they dominate web delivery. Embedded tracks survive being moved around as a single file, which is why broadcast prefers them.
Whatever the syntax, a caption file is a list of cues, and each cue is a start time, an end time and some text. Formats differ in what they add on top: positioning, styling, speaker metadata, and how precisely time is expressed.
That shared structure is why conversion between formats is possible at all, and why it is lossy in one direction — moving from a rich format to a plain one discards whatever the plain format cannot express.