Use of multimedia content on the web is growing, and the platform offers Post web managers expanded multimedia capabilities. It is important for Web developers to address usability needs now.

Guideline (b) of the Access Board standards states: “Equivalent alternatives for any multimedia presentation shall be synchronized with the presentation.”

The word “synchronized” is key. It is possible to create a separate file with the text of the contents of an audio file or a detailed description of a video or animation. However, to comply with section 508, the multimedia files must be synchronized with a text equivalent.

Captioning and Transcripts

The two typical methods of providing a multimedia alternative are captioning and transcripts. Provide captioning for video files and transcripts for audio files. Although a transcript isn’t synchronized, use this method for audio files since audio is technically one (not multi) media.

Captioning: Captioning is the on-screen textual presentation of audio material such as spoken dialogue. Unlike subtitles, captions have the option of being turned on or off.

Captioning Advantages

• Besides aiding those with hearing loss, captions also help persons with hearing disabilities.
• Increases learning and retention.
• Helps increase literacy.
• Aids in learning a second language.
• Facilitates the conveyance of audio content in environments that are noisy (e.g., a quiet library or no sound card or speakers).

Tips for Captioning

The method used to activate and deactivate accessibility features such as audio descriptions and captions should be intuitive to a person requiring that feature.

• Closed captioning: The text equivalent of the audio material is placed on a separate channel so users can turn it on and off. Use this format whenever possible, since it allows users to decide whether or not to display captions.
• Open captioning: Embeds the text permanently on the same layer as the video signal, so it cannot be turned off.