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Perceivable Guidelines

Lesson 2 of Section 3

Pre-recorded Media

Prerecorded audio-only media has an alternative format (such as text or visual), and prerecorded video-only media has an alternative format (such as text or audio).

In either case, the simplest way to satisfy this criteria is to provide a text alternative to the media format. This can be done by providing a link immediately after the media format to a text transcript of the audio or a text description of the events that occur in the video.


Captions are provided for all prerecorded audio content. This allows hearing impaired users to access the captions that are stored directly within the audio track.

This is for scenarios when you are providing an audio-only track that contains things like:

  • an audio book
  • a set of verbal instructions
  • a narration
  • music

This section is also for scenarios when you are providing a full video with audio, such as a YouTube video. It is highly recommended that you use a familiar and popular interface such as YouTube to provide your videos as they have a very user-friendly method of adding captions to videos. YouTube provides captioning support to get you started with closed-captions.

It is usually difficult to provide a cross-platform method of closed captioning for a pure audio source with no video. The best method to satisfy this requirement is to provide equivalent content that matches or exceeds the information that is provided in the auditory track. If the auditory track is an alternative to text-based content, you must clearly indicate this. Otherwise, you may provide SAMI and SMIL files for use with Quicktime, RealPlayer, and Windows Media Player.

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