What's the difference between subtitles and closed captions?
Subtitles transcribe spoken dialogue. Closed captions also describe non-speech audio (music, sound effects, speaker IDs) and are the accessibility standard.
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The terms are used interchangeably in casual speech, but they have different origins. Subtitles assume the viewer can hear the audio — they typically transcribe only spoken dialogue, often translated. Closed Captions (CC) is a US/broadcast term originating from line-21 captions (CEA-608, CEA-708): a toggleable text track designed for accessibility, which transcribes both speech and significant non-speech audio. SDH (Subtitles for the Deaf and Hard-of-hearing) is the streaming-era equivalent of CC, delivered as same-language subtitles. On modern streaming services the user-facing toggle usually says 'Subtitles/CC' and the distinction is invisible to viewers — but if you're authoring captions for accessibility compliance, follow CC/SDH conventions: speaker labels, music cues, and bracketed sound effects.
SRT for almost everything: video editors, YouTube, Vimeo, every major platform. VTT only when you're embedding video on a website with HTML5 <track>.
SRT (SubRip Subtitle) is a plain-text subtitle format with numbered cues and HH:MM:SS,mmm timestamps. It's the most universal subtitle format.