Using the following tools and techniques, you can provide most multimedia presentations in an accessible format.
- Synchronized Multimedia Integration Language (SMIL)
SMIL, pronounced “smile,” is a W3C web standard method of synchronizing video, main audio tracks, descriptive audio tracks, caption text, and other components of a multimedia presentation. Many media player applications, including the Quicktime Player and Real Player, can understand and use SMIL files. I believe Flash can also use SMIL, but do not know the extent of SMIL support in current versions of the Flash Player.
- MAGpie by NCAM
The Media Access Generator (MAGpie), developed by the National Center for Accessible Media (NCAM) is currently the best tool available for captioning video and is provided for download free-of-charge. MAGpie saves your multimedia presentations as SMIL files, which can then be exported to a variety of formats.
Knowbility offers a multimedia training session for AIR participants which covers basic installation and use of MAGpie.
- Descriptive audio tracks
Videos usually present on-screen information, such as a title or demonstrative action, that is not available in the audio track. Using SMIL, you can offer a descriptive audio track for vision-impaired users. Descriptive audio utilizes pauses in the main audio track to describe onscreen information.
- Video captions
Anytime you present a web video with an audio portion, you can present captions for the hearing-impaired. Captions are on-screen lines of text that display equivalents of audio content such as spoken words or sound effects.
- Transcripts
Spoken audio content can be presented with a plain text transcript for hearing-impaired. Keep in mind that this benefits more people than just those with disabilities. Non-disabled users may prefer to read the transcript instead of listening to the audio track. Also, search engines like Google can index the text transcripts, but not the audio files.