# Understanding Audio Description or Media Alternative (Prerecorded)

## In brief

Goal
  Prerecorded videos can be understood by more people.
What to do
  Provide a description of the visual content in videos.
Why it's important
  People who are blind or who cannot understand the visual content can have it described.

## Intent of Audio Description or Media Alternative (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. This Success Criterion describes two approaches, either of which can be used.

One approach is to provide audio description of the video content. 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.

The second approach involves providing all of the information in the synchronized media (both visual and auditory) in text form. An alternative for time-based media provides a running description of all that is going on in the synchronized media content. The alternative for time-based media reads something like a screenplay or book. Unlike audio description, the description of the video portion is not constrained to just the pauses in the existing dialogue. Full descriptions are provided of all visual information, including visual context, actions and expressions of actors, and any other visual material. In addition, non-speech sounds (laughter, off-screen voices, etc.) are described, and transcripts of all dialogue are included. The sequence of description and dialogue transcripts are the same as the sequence in the synchronized media itself. As a result, the alternative for time-based media can provide a much more complete representation of the synchronized media content than audio description alone.

If there is any interaction as part of the synchronized media presentation (e.g., "press now to answer the question") then the alternative for time-based media would provide hyperlinks or whatever is needed to provide the same functionality.

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.

See also 1.2.5 Audio Description (Prerecorded), 1.2.7 Extended Audio Description (Prerecorded) and 1.2.8 Media Alternative (Prerecorded).

## Benefits of Audio Description or Media Alternative (Prerecorded)

- This Success Criterion may help some people who have difficulty watching video or other synchronized media content, including people who have difficulty perceiving or understanding moving images.

## Examples of Audio Description or Media Alternative (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.)

An alternative for time-based media for a training video
  A company purchases a Training video for use by its employees and puts it on the companies intranet. The video involves explaining use of a new technology and has a person talking and showing things at the same time. Since there is no place to insert audio description of the visual demonstrations during gaps in dialogue, the company provides an alternative for time-based media that all employees, including those who cannot see the demonstrations, can use to better understand what is being presented.

## Resources for Audio Description or Media Alternative (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 or Media Alternative (Prerecorded)

### Sufficient Techniques for Audio Description or Media Alternative (Prerecorded)

- Providing an alternative for time-based media including any interaction using one of the following techniques

  - Placing a link to the transcript immediately next to the non-text content

- Linking to the alternative for time-based media using one of the following techniques

  - Using the body of the object element
- 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 or Media Alternative (Prerecorded)

### Failures for Audio Description or Media Alternative (Prerecorded)