# Understanding Audio-only and Video-only (Prerecorded)

## In brief

Goal
  Audio and video-only content can be understood by more people.
What to do
  Provide an alternative when content is perceivable with only one sense.
Why it's important
  People who can’t fully see or hear content can understand it.

## Intent of Audio-only and Video-only (Prerecorded)

The intent of this Success Criterion is to make information conveyed by prerecorded audio-only and prerecorded video-only content available to all users. Alternatives for time-based media that are text based make information accessible because text can be rendered through any sensory modality (for example, visual, auditory or tactile) to match the needs of the user. In the future, text could also be translated into symbols, sign language or simpler forms of the language (future).

An example of pre-recorded video with no audio information or user interaction is a silent movie. The purpose of the transcript is to provide an equivalent to what is presented visually. For prerecorded video content, authors have the option to provide an audio track. The purpose of the audio alternative is to be an equivalent to the video. This makes it possible for users with and without vision impairment to review content simultaneously. The approach can also make it easier for those with cognitive, language and learning disabilities to understand the content because it would provide parallel presentation.

A text equivalent is not required for audio that is provided as an equivalent for video with no audio information. For example, it is not required to caption audio description that is provided as an alternative to a silent movie.

See also 1.2.9: Audio-only (Live)

## Benefits of Audio-only and Video-only (Prerecorded)

- This Success Criterion helps people who have difficulty perceiving visual content. Assistive technology can read text alternatives aloud, present them visually, or convert them to braille.
- Alternatives for timed-based media that are text based may help some people who have difficulty understanding the meaning of prerecorded video content.
- People who are deaf, are hard of hearing, or who are having trouble understanding audio information for any reason can read the text presentation. Research is ongoing regarding automatic translation of text into sign language.
- People who are deaf-blind can read the text in braille.
- Additionally, text supports the ability to search for non-text content and to repurpose content in a variety of ways.

## Examples of Audio-only and Video-only (Prerecorded)

An audio recording of a speech
  The link to an audio clip says, "Chairman's speech to the assembly." A link to a text transcript is provided immediately after the link to the audio clip.
An audio recording of a press conference
  A Web page includes a link to an audio recording of a press conference that identifies the audio recording. The page also links to a text transcript of the press conference. The transcript includes a verbatim record of everything the speakers say. It identifies who is speaking as well as noting other significant sounds that are part of the recording, such as applause, laughter, questions from the audience, and so on.
An animation that illustrates how a car engine works
  An animation shows how a car engine works. There is no audio and the animation is part of a tutorial that describes how an engine works. Since the text of the tutorial already provides a full explanation, the media is an alternative for text and the text alternative includes only a brief description of the animation and refers to the tutorial text for more information.
A video-only file with an audio track
  A silent movie includes an audio track which includes a description of the action in the video.

## Resources for Audio-only and Video-only (Prerecorded)

- Overcoming the challenge of podcast transcription
- uiAccess list of transcription services
- Transcripts on the Web: Getting people to your podcasts and videos

## Techniques for Audio-only and Video-only (Prerecorded)

### Sufficient Techniques for Audio-only and Video-only (Prerecorded)

#### Situation A: If the content is prerecorded audio-only:

- Providing a full text transcript for the audio

#### Situation B: If the content is prerecorded video-only:

- Providing a full text transcript of the video content
- Providing audio that describes the important video content and describing it as such

### Additional Techniques (Advisory) for Audio-only and Video-only (Prerecorded)

### Failures for Audio-only and Video-only (Prerecorded)

- F30
- F67