Related information: What is "Descriptive Audio"? article from Ask Pecan.
Audio description (a.k.a. Descriptive Audio or Descriptive Video) is required when important information is visually shown on the screen that cannot be observed by a blind or vision-impaired individual.
WCAG 2.0 AA
The UC-wide policy standard is that “Electronic information must meet the Web Content Accessibility Guidelines (WCAG) 2.0 at level AA Success Criteria.”
WebAIM (generally agreed to be the most comprehensive resource on the web for both learning about accessibility and evaluating your website or product) has a helpful WCAG checklist at http://webaim.org/standards/wcag/checklist
For 1.2.5 Audio Description (Prerecorded) (Level AA), WebAIM’s Recommendation is:
- Audio descriptions are provided for all video content
- NOTE: Only required if the video conveys content visually that is not available in the default audio track.
About audio description
Audio description or video description or descriptive video service are three ways to refer to the ability to insert information into a secondary audio track that will give blind and visually-impaired individuals access to visual content on the screen. When available, visual description should be included in any transcript of a video. Although the ability to add descriptive tracks to audio has been available for over 20 years, it is still relatively an unknown field.
Today the top online streaming content sites offer the ability for users to access an alternative audio stream at no additional cost to their users. For example, all of Netflix original content and more have audio description available, and iTunes currently has the largest library of titles available to download with audio description.
When to describe
Audio description is required when important information is visually shown on the screen that cannot be observed by a blind or vision-impaired individual.
- An object is shown on the screen that is not referred to verbally but has importance to the information being conveyed.
- One of the participants on the screen points to a clearly identifiable object, i.e., a smoking gun and says "Is that the weapon?"
- At no time does the character say the word "gun" or the fact that the gun is "smoking."
- The listener is not able to determine the object being referred to, so audio description could help.
- However, if the actor had said anything about the smoking gun and indicated verbally like "that smoking gun must be the weapon" there is no need to describe the visuals.
Describing Academic Videos
For academic videos, the easiest and most cost-effective method is to teach instructors how to verbally describe any of their visual material. If instructors explain the purpose of the visual material, the required amount of additional audio description can be reduced or even eliminated.
When looking at academic videos, the need for further description of displayed visuals is often critical to not only blind and visually-impaired individuals but to the viewing audience as a whole:
- A majority of content today is viewed on small screens or in situations where the user may not be able to visually see what is being referred to on the screen.
- Many students will watch videos on their mobile phones while they are commuting on public transit or riding in a car.
- An instructor’s video includes a diagram
- Instead of saying "You will note the relationships in this diagram," the instructor can say "You will note that item 1 and item 3 directly connect to item 4 but item 5 only connects to item 2."
- By using this kind of language when referencing images, faculty can better teach students across the spectrum of learning styles
One of the other times that audio description is required is for text written on the screen. If the text is not spoken by a voiceover or one of the speakers within the video, a descriptive audio track should be added to read this text. Alternatively, if the video contains a static image or “talking head” type content, it is not necessary to include audio description.
Adding description in the main audio track of the video also improves searchability by including keywords that users might be searching for in the text transcript, which is indexed by search engines.
Ways to create audio description
Although audio descriptions have been available since approximately 1990, there are still limited choices as to how to create effective descriptions.
Below are two tools that can be used for audio description:
- When looking for a video player for web content, consider the "Able Player" plug-in, which was created by a consortium of universities across the United States and around the world. The "Able Player" facilitates captioning, audio description, and is built for accessibility.
- Another tool to consider is "YouDescribe", which allows a user to search for a YouTube video and add a audio description. It provides a unique link directly to the video that includes the audio description. This tool was created with a national research grant and allows anyone to add a descriptive audio track to any YouTube video.
The first thing to note is that there is a great deal of content already available that is described. If you are using a publicly-available video title, there may already be descriptive video available. There is no single source for searching audio description, and it might take a little bit of hunting to find if your title has already been described. Here is one the most extensive databases, but is not complete: Audio Description Project
Unlike captioning, audio description should be done by someone with a clear voice. Audio description does require some very specific training, but that often takes less than a day. Audio describers can be students, staff, and faculty themselves, or volunteers from the community. Here is a resource on how to train people when providing audio descriptions: Description Key
The WGBH public broadcasting station in Chicago has been a leader in the accessibility of video content for a long time:
- They were the first to include audio description in many of their offerings.
- They have led the research and development of much of the technology used for video accessibility today.
- WGBH has done some extensive work on including text description of HTML5 videos on the web.
- Currently WGBH has a grant to create a free and open source application for creation of captions and audio descriptions.
- The WGBH Media Access Group has many resources available to the public.
There are also audio description providers, which you can use to outsource described video. See the Audio Description Project's list of vendors.