Captioning

Captioning is the process of displaying text that represents spoken dialogue and relevant audio for audiovisual media. It supports accessibility for deaf and hard-of-hearing viewers and can aid understanding for learners and non-native speakers. Captions and subtitles are related but distinct: captions convey sound cues in addition to dialogue, while subtitles translate dialogue. Captions can be closed (toggleable) or open (burned into the video).

Caption types include transcription captions that render dialogue with speaker labels, and indications of non-speech sounds. There are live captions produced in real time and pre-produced captions prepared with the footage. A typical caption track covers dialogue, speakers, sound effects, and music cues.

Captioning involves transcription, timing, and encoding. Transcripts are synchronized to video using time codes. Web formats such as SRT and WebVTT are common online; broadcast captions use specialized streams. Quality control emphasizes accuracy, punctuation, legibility, and proper timing, with many workflows combining automated speech recognition and human review.

Accessibility and regulation: Many regions require captions for broadcast or online video to improve accessibility. Platforms provide automatic captions, often edited for accuracy, and professional captioners ensure high quality for critical content.

Applications include film, television, education, live events, corporate communications, and social media. Challenges include background noise, overlapping dialogue, accents, and fast pace. Benefits include wider reach, improved comprehension, language learning support, and regulatory compliance.