# Understanding Captions (Prerecorded)

## In brief

Goal
  Videos can be played with captions.
What to do
  Provide synchronized text for audio content in existing videos.
Why it's important
  People who are deaf or hard of hearing can understand audio in videos.

## Intent of Captions (Prerecorded)

The intent of this Success Criterion is to enable people who are deaf or hard of hearing to watch synchronized media presentations. Captions provide the part of the content available via the audio track. Captions not only include dialogue, but identify who is speaking and include non-speech information conveyed through sound, including meaningful sound effects.

It is acknowledged that at the present time there may be difficulty in creating captions for time-sensitive material and this may result in the author being faced with the choice of delaying the information until captions are available, or publishing time-sensitive content that is inaccessible to the deaf, at least for the interval until captions are available. Over time, the tools for captioning as well as building the captioning into the delivery process can shorten or eliminate such delays.

Captions are not needed when the synchronized media is, itself, an alternate presentation of information that is also presented via text on the Web page. For example, if information on a page is accompanied by a synchronized media presentation that presents no more information than is already presented in text, but is easier for people with cognitive, language, or learning disabilities to understand, then it would not need to be captioned since the information is already presented on the page in text or in text alternatives (e.g., for images).

See also 1.2.4: Captions (Live).

## Benefits of Captions (Prerecorded)

- People who are deaf or have a hearing loss can access the auditory information in the synchronized media content through captions.

## Examples of Captions (Prerecorded)

- A captioned tutorial

  A video clip shows how to tie a knot. The captions read,

  "(music)

  Using rope to tie knots was an important skill

  for the likes of sailors, soldiers and woodsmen.."

  From Sample Transcript Formatting by Whit Anderson.

- A complex legal document contains synchronized media clips for different paragraphs that show a person speaking the contents of the paragraph. Each clip is associated with its corresponding paragraph. No captions are provided for the synchronized media.
- An instruction manual containing a description of a part and its necessary orientation is accompanied by a synchronized media clip showing the part in its correct orientation. No captions are provided for the synchronized media clip.

- An orchestra provides captions for videos of performances. In addition to capturing dialog and lyrics verbatim, captions identify non-vocal music by title, movement, composer, and any information that will help the user comprehend the nature of the audio. For instance captions read,

  "[Orchestral Suite No. 3.2 in D major, BWV 1068, Air]

  [Johann Sebastian Bach, Composer]

  ♪ Calm melody with a slow tempo ♪"

  Style guides for captions may differ among different languages.

## Resources for Captions (Prerecorded)

### Guides to Captioning

- BBC: Subtitle Guidelines
- Captioning Key: Guidelines and Preferred Techniques
- Best Practices in Online Captioning

### SMIL Resources

- Synchronized Multimedia Integration Language (SMIL) 3.0
- Accessibility Features of SMIL

### Other Captioning Resources

- National Center for Accessible Media
- WebAIM: Captioning Resource List

## Techniques for Captions (Prerecorded)

### Sufficient Techniques for Captions (Prerecorded)

- Providing open (always visible) captions
- Providing closed captions using any readily available media format that has a video player that supports closed captioning

- Providing closed captions using any of the technology-specific techniques below

  - Providing captions through synchronized text streams in SMIL 1.0
  - Providing captions through synchronized text streams in SMIL 2.0
  - Using the track element to provide captions

### Additional Techniques (Advisory) for Captions (Prerecorded)

### Failures for Captions (Prerecorded)

- Failure of Success Criterion 1.2.2 due to captions omitting some dialogue or important sound effects
- Failure of Success Criterion 1.2.2 by providing synchronized media without captions when the synchronized media presents more information than is presented on the page text.
- Failure of Success Criterion 1.2.2 and 1.2.8 due to not labeling a synchronized media alternative to text as an alternative