Transcripts, captions, subtitles, and audio description meet different needs. For our work here at Orbis, we use transcripts or captions to meet most of the ADA compliance requirements for our digital assets. When to use one or both depends on the content and context.
Basic Transcripts
Basic transcripts are text-based documents for speech in an audio track. Transcripts provide a media alternative for people with hearing loss. Transcripts are adequate for speech-only presentations, such as podcasts. For more information, view this
basic transcript example.
Transcripts are not an equivalent substitution for captions to a video because the words separate from the moving images may lose meaning and the non-speech elements are lost. However, for videos of an instructor talking to the camera (talking head video) with no other visuals (e.g., a simple welcome message), captions are preferred, but if a transcript already exists, making an accessible version of the transcript may be adequate to meet some accommodation requests.
Indexed Transcripts (Orbis term)
An indexed transcript provides a media alternative to presentations such as narrated PowerPoint slides. Indexed transcripts are required for speech and visual presentations when the visual elements are not live action, animation, or decorative. For example, an instructor narrates a slide presentation about bottleneck concepts that includes images that convey content. The accompanying transcript may include the images used in the presentation or reference the slide number if the student can access the slides while reading the transcript. For more information, view this
indexed transcript example.
Note: Indexed transcripts do not meet accessibility needs of people who are blind or deaf-blind. Descriptive transcripts are required for people who are deaf-blind.
Descriptive Transcripts
Descriptive transcripts are required to provide visual content to people who are both deaf and blind. Descriptive transcripts include full descriptions of the visual content that accompany an audio track in a presentation or video. For universal design considerations, a descriptive transcript may be a media alternative for people who have difficulty processing auditory information and people who cannot focus and comprehend auditory or visual information. They may work for people who are blind or have low vision if the non-decorative visuals are described in detail along with the speech elements, and the document is completely accessible by a screen reader. For an example of a descriptive transcript, visit the
Video Captions page on the World Wide Web Consortium (W3C) Web Accessibility Initiative (WAI) website.
Captions
Captions are either open or closed. Open captions are part of the video and cannot be turned off. Closed captions allow you to turn them on or off. Captions include non-speech sounds, such as music or sound effects. They are an accommodation for people with a hearing loss. Captions are not accessible to a screen reader and, therefore, are not appropriate accommodation for people who are blind or have low vision. For an example of a caption file format, view this
SRT file excerpt.
Subtitles
Subtitles translate speech into the viewer’s preferred language and typically do not include non-speech sounds. Subtitles, therefore, are not an appropriate accommodation for a person with a hearing loss. Subtitles are not accessible by a screen reader and, therefore, are not an appropriate accommodation for a person who is blind or has low vision. For an example, view the Orbis
generic faculty course welcome message.
Historically, subtitles are often referred to interchangeably with captions. In recent years, producers of film and video content have combined the elements needed for captions and subtitles into one (for example, Subtitles for the Deaf and Hard of Hearing [SDH]), which include non-speech elements.
Audio Description
Audio description is used by people who are blind or have low vision. It is an audio track that describes the visual content essential to understanding the video or film, such as settings, scene changes, character actions, or onscreen text. The descriptions are typically inserted during pauses in dialogue of the original audio track of the film or video. For an example of audio description, view
Frozen - Trailer With Audio Description.
Orbis does not provide audio description for videos. This is noted in our Accessibility Conformance Report available to our partners. For video or storyline presentations, such as an onscreen tour through the LMS (learning management system), a media alternative is required.