Web checklist

The purpose of this checkpoint is to provide a way for blind or visually impaired people to access the visual information that is provided in multimedia, and for a hearing impaired or deaf user to access the information in a multimedia presentation. The visual information should be described either in audio format or in a full multimedia text alternative.

An audio description complements the existing audio track with information that a blind or visually impaired person would not otherwise know. During pauses in the existing audio track, a narrator describes the important visual details that are not already explained in the soundtrack.

A full multimedia text alternative describes everything that is happening in the multimedia and is not limited to the pauses in dialogue. In addition to the visual information, the text alternative also includes a transcript of all dialogue, as well as textual representations of all of the video, audio, and interaction from the multimedia. This enables a blind or visually impaired user to have the same information as a sighted user.

People who are deaf, hard of hearing, or have trouble understanding audio information can read the text presentation as well.

To comply with this checkpoint, you must either meet techniques 1, 2 and 3 defined below, OR you must meet technique 4.

These techniques are defined in WCAG 2.0 Level A Success Criterion 1.2.1 (link resides outside of ibm.com) and WCAG 2.0 Level A Success Criterion 1.2.3 (link resides outside of ibm.com).

1. For video with audio: Provide audio descriptions of video including any interaction that presents equivalent information for prerecorded multimedia.
2. For audio-only: Provide an alternative for time-based media that presents equivalent information for prerecorded audio-only content.
3. For video-only: Provide either an alternative for time-based media or an audio track that presents equivalent information for prerecorded video-only content.
4. Media alternative: Provide a full multimedia text alternative.

Note: The examples presented in the techniques are not exhaustive. They are meant to illustrate the spirit of this checkpoint.

General examples

1. For video with audio: Provide audio descriptions of video, or a full multimedia text alternative, including any interaction that presents equivalent information for prerecorded multimedia.

   To comply with this technique, you must implement at least one of the following examples.

   General example 1

   Provide a soundtrack that includes an audio description.

   • The National Center for Accessible Multimedia, which is part of the Media Access Group at WGBH, maintains a small multimedia clip that shows the opening to the movie "The Lion King". The clip contains an audio description, as well as captions. Please visit the NCAM site to play the video clip (6.4MB, MOV File) and to hear the audio descriptions. If this were the only version of the movie available, it would satisfy this example.
   • Provide a sound track that includes audio description AND associate it with the synchronized media content. This is demonstrated by the Lion King example above. The audio description was added to the original soundtrack during pauses in the dialogue. The original version of the movie is still available without an audio description.

   For additional information, refer to the WCAG 2.0 examples of providing a second user-selectable audio track that includes audio descriptions (link resides outside of ibm.com).

2. For audio-only: Provide an alternative for time-based media that presents equivalent information for prerecorded audio-only content.

   General example 2

   Provide a transcript for an audio-only file, such as a podcast. Hearing impaired users may not be able to listen to a podcast (or any other audio-only format). Providing a transcript ensures full access to the content of the audio-only file for all users. The transcript must identify the speakers and include descriptions of any other sounds heard, such as sound effects.

3. For video-only: Provide either an alternative for time-based media or an audio track that presents equivalent information for prerecorded video-only content.

   General example 3

   Provide an audio description of a video-only file. An audio description of the video would serve as an alternative format for a blind user. The audio description should describe everything that is happening in the video and should be available either as a separate downloadable file or it should be synchronized with the video.

4. Media alternative: Provide a full multimedia text alternative

   General example 4

   Provide a full text alternative for a video-only file. An example of video-only content would be a training module that captures a software demonstration. It is very common for a tool to be used to record and play back the actions that take place on the user's computer without added audio. Other examples include silent movies or an animation with no sound.

   A full text alternative of the file would describe, in text, exactly what is happening on the screen. All mouse clicks, screen shots, and images should be described, as well as any interaction or other information that is being conveyed in the video.

   General example 5

   Provide a full synchronized media text alternative, including any interaction. A full multimedia text alternative will allow a person to experience all of the video, audio, and interaction that the multimedia presents, but in an alternative format. Using the Lion King example above, you could provide a text alternative to a movie, which would be very much like a screenplay, only modified to match exactly what happens on the screen. The alternative would include everything that would be found in a transcript, along with the text from the audio description, sounds, scene changes, character expressions, and additional descriptive text if necessary.

   For additional information, refer to the WCAG 2.0 examples of providing an alternative for time-based media (link resides outside of ibm.com).

   Required unit tests for general development techniques 1-5

   Manually perform the following unit tests.

   • Locate the multimedia in the content.
   • For prerecorded audio+video content, manually verify that one or more of the following is true:
     • A full synchronized media text alternative (screenplay) is provided that includes both the audio information (dialog and a description of essential sound effects) and the video information (a description of essential visual content).
     • A synchronized soundtrack with a audio description is provided in which gaps in dialogue are used to convey essential information regarding visual content.
     • The user can access and operate any of the above alternatives.
   • For prerecorded audio-only content manually verify that a text transcript is provided that contains:
     • All essential dialog, identification of the speakers and a description of all essential sound effects for the audio-only content.
   • For prerecorded video-only content manually verify that equivalent audio track as a separate file that the user can access or synchronized   with the video is provided that contains
     • All essential dialog, identification of speakers and a description of all essential visual aspects along with any interactions for the video-only content.
   • When full multimedia text alternative is provide verify that the full text transcript describes all essential video, audio, interactions along with any sounds, scene changes, character expressions, and additional descriptive text if necessary to fully describe the multimedia.

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