Overview

This lesson will address the importance of captions, transcripts, and audio descriptions.

Core Concepts

Captions

Captions are synchronized text that matches the audio component of a video ("synchronized" means that the text appears at roughly the same time as the matching audio). This includes both spoken words and written descriptions of important sounds, like music, laughter, or sound effects. Captions should also identify which person is speaking or making noise, when there are multiple people or voices in a video.

Closed captions are captions that the person viewing the video can control. A viewer can turn them on or off, and if the video player supports it, they can change the size, color, and font of the text to make it easier to read. Closed captions should be used in most circumstances.

Open captions are part of the video itself (they're "burned in" to the video). They're always present, cannot be turned off, and cannot be customized. Open captions are generally only appropriate when there will be no way for viewers to control them, for example a video screen for the audience at a performance or sporting event.

Some people, including many who have attentional or cognitive disabilities or who are neurodivergent find captions to be distracting, which is another reason why closed captions are preferred over open captions.

Captions are essential for many people who are Deaf or hard of hearing to understand audio content in videos, and also benefit people who have language impairments, people who are in noisy environments, and others.

Automated Captions

Many video services and hosting platforms, like YouTube, can automatically generate captions. Unfortunately, while automated captioning is getting better, it's not totally accurate. The accuracy of automated captions is impacted by everything from microphone quality to a speaker's accent to how common the words used are. Automated captions are not good enough – for pre-recorded videos, they can be a helpful starting point, but need to be edited for accuracy and missing information (like non-speech sounds and speaker information) frequently needs to be added in.

Subtitles

Subtitles are synchronized text that translates one language into another. In some places, the terms "captions" and "subtitles" are used interchangeably, but it's standard in accessibility terminology to differentiate the two.

Transcripts

Transcripts present the text as captions, but instead of being synchronized and present in small chunks that match the timing in the video like captions, transcripts are a single, full document with all of the text. Transcripts don't replace the need for captions, but are a great alternative way to present information for those who prefer a text-only option, and transcripts have the advantage of being easily searchable.

Audio Descriptions

Audio descriptions are the opposite of captions. Audio descriptions provide auditory explanations of visual content for people who may not be able to see the video. Audio descriptions include information about actions, people, and other visuals, as well as reading out text that is on screen. Creating a separate audio description track for a video (which allows the person viewing to select whether they want the original or the audio description version of the audio) can be very difficult, but if you're creating a video presentation yourself, you can eliminate the need for a separate audio track by ensuring that audio descriptions are part of main audio. For example, if you're giving or recording a presentation with a PowerPoint slide deck, you can read out the on-screen text and describe the visuals on each slide as you talk.

CART

When an individual who is Deaf or hard of hearing needs accurate captions during a live event, CART (Communication Access Real-Time) services must be provided. Unlike automated captions, CART involves a real person typing. Professional CART services generally employ people trained to type quickly and accurately, and capture the relevant information. Captioners are frequently located off-site, using a microphone or audio feed of the event and with captions provided via a web-based interface on a phone or laptop. Given the additional challenges in arranging CART services, they are typically only used when requested or when an event will be large.

Sign Language Interpretation

Sign languages are languages that use combinations of hand shapes and motions, facial expressions, body position, and other visual indicators. Sign languages have their own grammar and vocabulary (they're not word-for-word translations of spoken language), and are not universal. American Sign Language (ASL) is the most common sign language in the U.S., but there are many other sign languages around the world. Even other predominantly English-speaking countries have unique sign languages, like British Sign Language (BSL). ASL also has dialects, like Black ASL, which has a different vocabulary and syntax, and phonology from ASL, which is the result of segregation in the 1800s and 1900s dividing signing communities in the United States.

While sign language interpretation (not "translation") can be helpful or necessary for some people to understand audio content, it is not typically required by digital accessibility standards, and is therefore an accommodation that requires special arrangements. Like CART services, sign language interpretation is generally only provided when requested or for large events. Sign language interpreters are easy to set up in systems like Zoom, where they can have direct access to audio and be displayed on video.

The UO Experience

"I am deaf. For the majority of the doctoral graduation ceremonies, I was just sitting there waiting for the captions to work or for the interpreter to be visible and/or sign." – UO PhD graduate

"Most, if not all online course videos should either have subtitles or a transcript. Many people with ADHD and other learning differences benefit from the combination of audio and visual stimulation. Many people with ADHD also have a comorbid audio-processing disorder, which can make it challenging to retain information delivered only through audio. While some professors make an active effort to only include materials that provide subtitles, some professors do not. This means that people with ADHD and other learning differences may experience more challenges when trying to complete coursework." – Rosie, UO undergraduate student

Additional Resources

Captions, Transcripts, and Audio Descriptions from WebAIM – a helpful overview with examples of captions and audio descriptions
Captions/Subtitles from the W3C Web Accessibility Initiative
Captioning and CART from the Hearing Loss Association of America
Communication Access Realtime Translation from National Association of the Deaf