Audio descriptions are audio tracks or transcripts that contain narration of onscreen movement or visuals. They are mainly intended for users with visual impairments such as blind and low vision users. Audio descriptions have a narrator that describes
any important content that is not conveyed through audio such as settings, graphics, and on-screen activity. They are commonly used for pre-recorded material such as video tutorials, video resources, and instructional videos.
There are three types of audio descriptions:
Closed audio description: Users can turn the audio descriptions on or off
Open audio description: The audio description is played automatically and users are unable to turn the audio description off
Real-time audio description: Live commentary or narration is provided by a trained audio describer. This is most commonly found in live theater and live events
Do I need audio descriptions?
Yes – if the video contains graphic elements that are not explained by the narrator in the video.
No – if the narrator in the video describes all the actions and graphic elements portrayed in the video. If a video does not portray content through visuals it does not need audio descriptions, but the video would require captioning.
Built-in video descriptions: The best and easiest way to create audio descriptions is to have the narrator or speaker in the video describe the visuals and important onscreen action while recording the audio. If the original audio of the
video describes illustrations, movement, and any sort of visual content then, they are not required to create an audio description.
Create separate videos: The second-best option is to create two versions of the video. The first can include the original audio for the video. The second video can include the audio description track.
Two audio tracks: The last option is to have two audio tracks attached to the video and allow users to choose between the original audio and audio description.
Audio descriptions can be implemented using HTML5 elements. Essentially, this method is not record by an audio describer, but the script is embedded so that assistive technology is able announce the content to users.
The <video> and <track> element are used to create the script. The track element allows content creators to embed the audio description transcript and have the timing synchronized with the video. There are five types of tracks content creators could choose from: captions, subtitles, chapters metadata, and descriptions. The precise timing allows for the text to be read by screen readers during general reading pauses.
Example: The following is an example of a Web Video Text Tracks text file from Terrill Thompson’s blog, an accessibility specialists from the University of Washington. Audio Description Example
00:00:00.000 --> 00:00:05.000
00:00:40.000 --> 00:00:45.000
Videos that contain plenty of visual information such as graphs and charts may be time-consuming to audio describe. As a result, instead of content creators making the audio description themselves, most seek the creation of audio descriptions through vendors. Vendors have professional describers and writers to translate the descriptive visual content. It is recommended for audio description creators to understand the context included in the video. Some audio description creators might miss key points in the multimedia when attempting to describe visual content. Prices may vary by Vendor as they vary by project and video basis.
Example 1: Universal Pictures Audio file and Video
The example below is a video of the Universal Pictures intro/ logo. Above the video, however, there is a link to the audio track of an audio description. In the audio description, the audio describer explains the "Universal" logo shown in all Universal
Pictures films. The describer begins by describing the setting in the video first (e.g.:"a black sky a sliver of sunlight crests the earth..."). This is followed by a description of the words on the screen.
The transcript shows the correct method to use the audio and audio description tracks. In the video, TV host, Jeff Corwin is the speaker. In addition to Jeff, a "female narrator's voice" serves as the audio describer. When Jeff swims towards an
object and the female narrator announced his movement in the transcript by saying, "Jeff swims among the fish and kelp in the deep water. He points out a flower shape". Jeff then begins to talk about the flower shape object. For users who are
unable to visually see the content in the video, it would be difficult for them to comprehend what Jeff is referring to. A written transcript is located below the video.
Jeff Corwin: Hey there. I'm Jeff Corwin. So you can enjoy the full TV experience, many shows now provide video description. Many people who are blind or have difficulty understanding visual cues find video description. The description is available through your TV set-up menu.
Female narrator's voice: Jeff swims among the fish and kelp in deep water. He points out a flower shape.
Jeff Corwin: There are its tentacles, and there's its mouth.
Male narrator's voice: For more information, visit afb.org.
This example of an audio transcript displays what type of visual content in a video is announced. For example, the describer in the transcript announces the title that appears when the video begins. The describer reads the title and reports what the
teacher is doing, and what the image the teacher is showing looks like. The describer then announces when the teacher hands students two wooden sticks. It was important for the describer to announce this because it gives an insight on what the teacher
will do next. The teacher says they will pretend to be birds, and the describer says the teacher held the two sticks near her mouth in the shape of a beak. Without this additional information provided by the audio describer, viewers with visual impairments
would not have known about everything that was happening in the video.
Describer: A title, "Teaching Evolution Case Studies. Bonnie Chen." A teacher shows photographs of birds with long, thin beaks.
Bonnie Chen: "These photos were all taken at the Everglades."
Describer: The teacher hands each student two flat, thin wooden sticks.
Bonnie Chen: "Today you will pretend to be a species of wading bird that has a beak like this."
Describer: The teacher holds two of the sticks to her mouth making the shape of a beak.
Audio descriptions can be time-consuming and costly. When designing videos avoid the need of audio descriptions by embedding the descriptions in the original narration of the video. For example, if a video contains a presentation showing four key sections; the narrator might say, “The four key sections are…” This will provide all users with the key points of a video without having to add audio descriptions.
YouTube currently does not support audio descriptions. If you are using YouTube, it is recommended to upload two versions of the video; one with the audio description and one with the default audio.
The narration should not overlap the audio of the original video.
Visual presentations with no audio do not require audio description. However, they do require text transcripts to translate all the visual elements, graphics, figures, etc. that are present.
Writing Audio Descriptions
Narrators should depict what is seen without interpretation or comment.
The passage of time within scenes should be described.
The narrator should describe events in present tense.
Narrators should be observant and announce movements, visuals, or body language.
For live performances, the audio describer should attend rehearsals, and read the script prior to the show to prepare an audio description.