Understanding WCAG 2.0

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Captions (Prerecorded):
Understanding SC 1.2.2

1.2.2 Captions (Prerecorded): Captions are provided for all prerecorded audio content in synchronized media, except when the media is a media alternative for text and is clearly labeled as such. (Level A)

Intent of this Success Criterion

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 Understanding Success Criterion 1.2.4 Captions (Live).

Specific Benefits of Success Criterion 1.2.2:

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

Examples of Success Criterion 1.2.2

Related Resources

Resources are for information purposes only, no endorsement implied.

Guides to Captioning

SMIL Resources

Other Captioning Resources

Captioning Tools

Techniques and Failures for Success Criterion 1.2.2 - Captions (Prerecorded)

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this Success Criterion. [begin change]However, it is not necessary to use these particular techniques. Any techniques used only satisfy the Success Criterion if all of the WCAG 2.0 conformance requirementshave been met.[end change]

Additional Techniques (Advisory) for 1.2.2

Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.

  • Providing a note saying "No sound is used in this clip" for video-only clips (future link)

  • Using SMIL 1.0 to provide captions for all languages for which there are audio tracks (future link)

  • Using SMIL 2.0 to provide captions for all languages for which there are audio tracks (future link)

Key Terms


the technology of sound reproduction

Note: Audio can be created synthetically (including speech synthesis), recorded from real world sounds, or both.


synchronized visual and/or text alternative for both speech and non-speech audio information needed to understand the media content

Note 1: Captions are similar to dialogue-only subtitles except captions convey not only the content of spoken dialogue, but also equivalents for non-dialogue audio information needed to understand the program content, including sound effects, music, laughter, speaker identification and location.

Note 2: Closed Captions are equivalents that can be turned on and off with some players.

Note 3: Open Captions are any captions that cannot be turned off. For example, if the captions are visual equivalent images of text embedded in video.

Note 4: Captions should not obscure or obstruct relevant information in the video.

Note 5: In some countries, captions are called subtitles.

Note 6: Audio descriptions can be, but do not need to be, captioned since they are descriptions of information that is already presented visually.

media alternative for text

media that presents no more information than is already presented in text (directly or via text alternatives)

Note: A media alternative for text is provided for those who benefit from alternate representations of text. Media alternatives for text may be audio-only, video-only (including sign-language video), or audio-video.


information that is not live

synchronized media

audio or video synchronized with another format for presenting information and/or with time-based interactive components, unless the media is a media alternative for text that is clearly labeled as such