Why should I make audio and video files accessible?
Transcripts, captions and audio descriptions make multimedia such as video and audio accessible to people with vision and hearing impairments and learning disabilities, and to native speakers of different languages.
Closed captions: A text-based description of a video’s dialogue including speaker identification and other relevant audio information, (music, sound effects, etc.) that appears usually at the bottom of the screen, and is synchronized with the media.
Automatic Speech Recognition (ASR) are automatic machine generated captions that require human editing to ensure accessibility.
Audio description, caption and transcript accessibility requires time. It is best to hire a professional captioning service to meet ADA requirements.
Transcripts: Written or printed version of material originally presented in another medium. Transcripts allow users to search for specific information or keywords contained in the media.
It is suggested to include a transcript if you have visual elements in your video, for example images or graphs, that need to be explained if there is no voice narration explaining them.
Planning for accessibility: Scripting all spoken content in advance will ensure images are properly described and make the captioning process easier.
- Text should not exceed 42 characters per line.
- Each caption should contain no more than two lines of text.
- Characters per second should not exceed 15.
- Ensure text/background color combinations meet color contrast standards (use WebAim contrast Checker).