Online Video Captioning Best Practices
Captions allow deaf viewers to understand the spoken content of videos by displaying words in sync with audio. Below are some generally accepted captioning standards for ADA best practices and compliance.
ADA Best Practices for Caption Timing and Positioning:
- Align text left
- Each caption frame should hold 1 to 3 lines of text onscreen at a time, viewable for a duration of 3 to 7 seconds. Each line should not exceed 32 characters.
- Each caption frame should be replaced by another caption.
- All caption frames should be precisely time-synched to the audio.
- A caption frame should be repositioned if it obscures onscreen text or other essential visual elements.
ADA Best Practices for Caption Style and Formatting:
- Spelling should be at least 99% accurate.
- When multiple speakers are present, it is helpful to identify who is speaking, especially when the video does not make this clear.
- Numbered: Label as SPEAKER 1: SPEAKER 2: SPEAKER 3: according to when they chronologically appear in the file.
- Classroom: Label as PROFESSOR: and STUDENT: All student interaction will be collectively labeled as STUDENT.
- Interview: Label as INTERVIEWER: and SUBJECT: For multiple interviewers or subjects use INTERVIEWER 1: INTERVIEWER 2: SUBJECT 1: SUBJECT 2:
- Presentation: Label as PRESENTER: and AUDIENCE: All audience interaction will be collectively labeled as AUDIENCE:
- Focus Group: Use MODERATOR: for moderation, and MALE SPEAKER:, and FEMALE SPEAKER: for all participants.
- Both upper and lowercase letters should be used.
- The font should be a non-serif, such as Helvetica medium, 22 pt font
- Non-speech sounds like [MUSIC] or [LAUGHTER] should be added in square brackets.
- Punctuation should be used for maximum clarity in the text, not necessarily for textbook style.
- Captions should preserve and identify slang or accents.