Checkpoint 1.2.2 Captions (Prerecorded)

Captions are provided for all prerecorded audio content in synchronized media. (Level A)

Rationale

Captions provide a text equivalent for audio content. They are synchronized to appear on screen with the relevant audio information, such as dialogue, music, and sound effects.

Captions are of the following two types:

  • Open captions cannot be turned off by the user; they are typically burned into the image so that the user cannot adjust their appearance.
  • Closed captions can be turned on or off by the user. They are provided in a separate data stream that is synchronized with the multimedia. The user has the potential to alter their size, typeface and color.

The source material for captions can also serve as a transcript or be transformed by assistive technology into other formats. IBM provides tools and information on how to create captions.

Exception: Captions are not needed when the media itself is an alternate presentation of text information. 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 the media would not need to be captioned. Such media should be labelled as a media alternative.

Refer to Understanding 1.2.2 for more information (external link to WCAG).

Development Techniques

Review the General techniques as well as other tabs applicable to your technology.  Prioritize the use of technology-specific techniques, and implement the General techniques as needed. You are always required to find, understand and implement accessible code techniques to meet the checkpoint. The documented techniques and supplements are not exhaustive; they illustrate acceptable ways to achieve the spirit of the checkpoint. If numbered, techniques are in order of preference, with recommended techniques listed first. Where used, IBM information that complements the WCAG techniques is indicated as supplemental.

General techniques

Instructions: Items in this section can be used in combination to meet this checkpoint. Ensure you review WCAG Common Failures to avoid development mistakes.

Ensure captions are synchronized with the media, using one of these techniques:

General supplements

The following examples and comments provide additional information beyond that available in the WCAG techniques.

Ensuring captions are accurate, consumable and complete

The following recommended techniques encapsulate best practices for captioned content. More detailed guides to captioning are listed in the Related Resources section of Understanding 1.2.2.

  • Do not display more than three lines at one time.
  • Follow sentence capitalization and proper punctuation standards and use italics to emphasize words or sentences.
  • Accurately include all spoken content.
  • Place the speaker name in front of the caption each time a speaker changes.
  • Include information about background sounds, music, and other relevant information in parentheses. However, do not describe someone's physical appearance or race, unless those aspects are germane to the understanding of the video material.
  • Open captions use high contrasting colors and easy-to-read, sans-serif fonts.

Web (HTML, ARIA, CSS) techniques

Instructions: In addition to the General techniques, any item in this sections represents a technique deemed sufficient.

Meet G87: Providing closed captions with the following:

Mobile (iOS) techniques

There are no specific Mobile Native iOS technniques for this checkpoint. However, in addition to the General and Web techniques, the techniques in this section provide additional information and context for hybrid applications.

Hybrid techniques

Meet G87: Providing closed captions with the following:

Hybrid supplements

H95: Using the track element to provide captions

Eclipse techniques

There are no specific Eclipse techniques for this checkpoint. Refer to the General techniques section.

Windows-based (MSAA+IA2) techniques

There are no specific Windows-based (MSAA+IA2) techniques for this checkpoint. Refer to the General techniques section.


Most links in this checklist reside outside ibm.com at the Web Content Accessibility Guidelines (WCAG) 2.0. W3C Recommendation 11 December 2008: http://www.w3.org/TR/WCAG20/

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