# Understanding Audio Description (Prerecorded)

## In brief

Goal
  Videos can be played with audio descriptions.
What to do
  Provide a synchronized spoken description of the visual content in videos.
Why it's important
  People who cannot see or understand the visual content can hear about it while playing videos.

## Intent of Audio Description (Prerecorded)

The intent of this Success Criterion is to provide people who are blind or visually impaired access to the visual information in a synchronized media presentation. The audio description augments the audio portion of the presentation with the information needed when the video portion is not available. During existing pauses in dialogue, audio description provides information about actions, characters, scene changes, and on-screen text that are important and are not described or spoken in the main sound track.

For 1.2.3, 1.2.5, and 1.2.7, if all of the information in the video track is already provided in the audio track, no audio description is necessary.

1.2.3, 1.2.5, and 1.2.8 overlap somewhat with each other. This is to give the author some choice at the minimum conformance level, and to provide additional requirements at higher levels. At Level A in Success Criterion 1.2.3, authors do have the choice of providing either an audio description or a full text alternative. If they wish to conform at Level AA, under Success Criterion 1.2.5 authors must provide an audio description - a requirement already met if they chose that alternative for 1.2.3, otherwise an additional requirement. At Level AAA under Success Criterion 1.2.8 they must provide an extended text description. This is an additional requirement if both 1.2.3 and 1.2.5 were met by providing an audio description only. If 1.2.3 was met, however, by providing a text description, and the 1.2.5 requirement for an audio description was met, then 1.2.8 does not add new requirements.

## Benefits of Audio Description (Prerecorded)

- People who are blind or have low vision as well as those with cognitive limitations who have difficulty interpreting visually what is happening benefit from audio description of visual information.

## Examples of Audio Description (Prerecorded)

A movie with audio description

  Describer: A title, "Teaching Evolution Case Studies. Bonnie Chen." A teacher shows photographs of birds with long, thin beaks.

  Bonnie Chen: "These photos were all taken at the Everglades."

  Describer: The teacher hands each student two flat, thin wooden sticks.

  Bonnie Chen: "Today you will pretend to be a species of wading bird that has a beak like this."

  Describer: The teacher holds two of the sticks to her mouth making the shape of a beak.

  Transcript of audio based on the first few minutes of "Teaching Evolution Case Studies, Bonnie Chen" (copyright WGBH and Clear Blue Sky Productions, Inc.)

## Resources for Audio Description (Prerecorded)

- NCAM Rich Media Accessibility, Accessible SMIL Templates
- Standard Techniques in Audio Description
- Synchronized Multimedia Integration Language (SMIL) 1.0
- Synchronized Multimedia Integration Language (SMIL 2.0)
- Accessibility Features of SMIL

## Techniques for Audio Description (Prerecorded)

### Sufficient Techniques for Audio Description (Prerecorded)

- G78: Providing a second, user-selectable, audio track that includes audio descriptions

- Providing a version of a movie with audio descriptions using one of the following:

  - Providing audio description in SMIL 1.0
  - Providing audio description in SMIL 2.0
  - Using any player that supports audio and video

- Providing a movie with extended audio descriptions using one of the following:

  - Adding extended audio description in SMIL 1.0
  - Adding extended audio description in SMIL 2.0
  - Using any player that supports audio and video

### Additional Techniques (Advisory) for Audio Description (Prerecorded)

### Failures for Audio Description (Prerecorded)