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Audio description

Audio description is a separate narrative audio track that accompanies a video, describing important visual content for people who are unable to see the video. People who are blind can understand much of a video’s content by listening to its audio. However, if a video includes content that is only presented visually (e.g., on-screen text or key actions that are not obvious from the audio) this visual information must be described. This benefits people who are unable to see the video due to blindness or low vision. It also benefits users who are visually distracted, watching a video in the background while multitasking.

This is one of several features that are needed for making videos accessible. For additional information, see our IT Accessibility Checklist page on Audio and video.

Integrated description: avoiding the need for audio description

The need for audio description can be avoided by ensuring all important visual information is communicated verbally. Here are some examples:

  • Teamwork: Making IT Accessible at the University of Washington – This video features several speakers, whose names and affiliations are displayed visually with on-screen text. To avoid the need for audio description, each speaker introduces themselves the first time they speak, and a narrator reads the closing credits.
  • Integrated Described Video (IDV) – This website from Accessible Media, Inc. (AMI) includes a series of high-quality videos produced to educate on the benefits of integrated description.

Outsourcing audio description

The American Council of the Blind has compiled a comprehensive list of commercial services for producing audio description. The following subset of organizations provides description services at prices and turnaround times that seem to be a good match for higher education institutions.

The typical deliverables provided by professional audio description services are either an audio file with soundtrack and description mixed together, or an audio described version of the video, with the described audio replacing the original program audio. In either case, these can be made available to users by announcing that the video is “Also available with audio description”, where “audio description” is a link to the described version.

Extended audio description

In order for audio description to be inserted into a video, there must be enough audio space for the description to fit.  This need can be addressed early when scripting and editing a video, making sure to include audio gaps between speakers or in other places where description is likely to be required.

If there are too few gaps in the audio, extended description may be required.  With extended description, the video is paused temporarily in order to make room for the description, then resumes playback when the description is finished.  When outsourcing audio description, most vendors provide extended description as an option for a higher price. It’s best to arrange this with the vendor and let them determine whether there’s a need for extended description (it’s impossible to know without knowing what needs to be described).

Note that if you’re delivering two videos, one with audio description and one without, extended description will make the described video longer than the original video.  Therefore, the two videos will need to be captioned separately.

Text-based audio description

For video on web pages, the HTML5 specification includes support for audio description in a WebVTT file (a time-stamped text file, which can be used for a variety of purposes, including captions or descriptions). An advantage of this method is that it’s very easy to produce.  You can do so using any caption editor (see our Captions page for a list of free online tools) or you can create it from scratch in any simple text editor such as Notepad or TextEdit.

Although this method is part of the HTML5 specification, it currently is not natively supported by any browser. In order to use this method, you need to be using Able Player as your media player. Able Player is a free, open-source media player that was developed at the UW.  For more information about Able Player see our Media players page. Able Player supports text-based audio description using the speech output capabilities of modern web browsers.

Another advantage of using this method, and playing the video in Able Player,  is that extended description is controlled by the player.  It automatically pauses the video as needed to make room for description, so you can provide one version of the video,  with one caption file and one description file.