What is an audio description?
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 describe critical content that is not conveyed through audio such as settings, graphics, and on-screen activity. Audio descriptions 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: A trained audio describer provides live commentary or narration — a real-time audio description 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 represent content through visuals, it does not need audio descriptions, but the video would require captioning.
Why do we need descriptions?
- Access for individuals who are blind and low vision
- Auditory learners
- English language learners
- Autism spectrum
- No access to visual content
How to create an audio description
According to the Digital Gov article, How to Make Audio Descriptions there are three methods to creating audio descriptions.
- 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 significant onscreen action while recording the audio. If the original audio of the video describes illustrations, movement, and any 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 consist of 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.
Section 508/WCAG 2.0 Requirements
Audio descriptions are required if the normal audio narrative fails to describe all important visual information clearly. (WCAG 2.0: 1.2.5 Audio Description Prerecorded)
Text-Based Audio Description
Audio descriptions can be implemented using HTML5 elements. Essentially, this method is not recorded by an audio describer, but the script is embedded so that assistive technology is able to 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 specialist 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 critical 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 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..."). The introduction is followed by a description of the words on the screen.
Universal Pictures: Audio file of an audio description.
Example 2: Frozen film trailer with audio description
The example below is a video with audio description. The audio describer announces the movement of characters, their facial expressions and any on-screen action occurring in the video.
Example 3: Transcript Examples
The following is an audio description transcript provided by the American Foundation for the Blind.
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 see the content in the video visually, it would be difficult for them to comprehend what Jeff is referring to. There is a written transcript 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.
Transcript of audio based on the first few minutes of "Teaching Evolution Case Studies, Bonnie Chen" (copyright WGBH and Clear Blue Sky Productions, Inc.)
Read more about W3C examples of an audio description transcript
- Audio descriptions can be time-consuming and costly when designing videos. Avoid the need for 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 information 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 video with audio description and one with the default audio. Caption both videos.
- 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 they see without interpretation or comment.
- Describe the passage of time within scenes.
- The narrator should describe events in the 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 before the show to prepare an audio description.