Closed Captions
Timed on-screen text of a video's audio, which platforms index and viewers increasingly expect.
Closed captions are the timed text of a video's audio, displayed on screen and switchable off. They are an accessibility requirement for deaf and hard-of-hearing viewers, and platforms index them — so uploading an accurate caption file rather than relying on auto-generation is what makes a video findable by what is said in it.
Definition
Captions are supplied as a timed file, usually SRT or WebVTT, and differ from subtitles: captions also convey non-speech audio that matters to comprehension.
Auto-generated captions are a starting point, not a deliverable. They mishandle names, jargon and accents, and on technical content the errors land exactly on the terms someone would search for.
Why It Matters
Most social video is watched muted, so captions decide whether it is watched at all. On YouTube and similar platforms, the caption text is also searchable content.
Example
WEBVTT
00:00:01.000 --> 00:00:04.000
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