This page is in progress -
Why This is Important
Captions are primarily for Deaf/hard of hearing people to access audio in videos.
Blind and visually impaired people use screen readers to interact with websites and apps. A screen reader is a type of assistive tech that converts things on screen to audio and/or braille. It's important that things are understandable and interactive to screen readers.
Keyboard accessibility is essential for people who do not use a computer mouse (which might be because they have unpredictable or very specific movement due to a motor disability). Many Blind and visually impaired people also use keyboard interactions in order to use their screen reader.
Error support is accessible to people with a diversity of disabilities. A cognitive disability might affect how a person perceives and understands things. A physical disability might lead to unpredictable movement. Other factors such as environment, stress, and multi-tasking may also lead to errors.
In order to be accessible, gestures and interactions must account for people with physical and motor disabilities, who might have unpredictable or very specific movement.
Captions should encompass spoken word, music soundtrack, and other sounds in order to be accessible.
Captions and subtitles also make media more accessible for people in a variety of situations, including those with a different native language, those in noisy or very quiet environments, those who prefer visuals, etc.
This references WCAG criteria 1.2.2 Captions (Prerecorded) (Level A) and 1.2.4 Captions (Live) (Level AA)
Level AAA compliance is considered more difficult to meet because it requires more resources to fulfill. It also might encompass conflicting access needs (meaning what is accessible to some might be inaccessible to others). Use your best judgment of your target audience and your team's capabilities to determine if this is a pragmatic goal to reach.
How to Implement This
There are 2 main steps to adding captions to video - creating the transcript (i.e. converting audio to text) and then syncing the text to match the audio in the video.
Create the transcript
For creating the transcript, refer to Provide audio transcripts. Many of these tools recommended on that page are auto-captioning services that can be used to jumpstart the process, though some degree of manual transcribing and editing is necessary for accuracy.
In the process of creating the transcript, it's critical to keep in mind caption quality. According to the Described and Captioned Media Program (DCMP), quality captioning must be:
- Accurate - no errors
- Consistent - uniform style and presentation
- Clear - complete textual representation, including speaker identification and non-speech information
- Readable - visually readable in terms of timing, synchronization, and and visibility
- Equal - preserve the original meaning and intention
See DCMP Captioning Key for more.
The "equal" rule applies specifically to censorship of what some people consider unsavory material, such as profanity and swearing. Ahmed Kahlifa (a Deaf educational blogger) explains why censorship is a barrier against information access - Why you should never censor audible profanity in video captions?
Note: I personally agree with Deaf activists and consider censorship of profanity to be very patronizing. However in the case of racist, ableist, or otherwise offensive slurs, I do think the captioner is socially obligated to partially censor the slur.
Syncing captions to audio
There are 2 ways of adding captions to video - open and closed captions. What you choose will depend on your audience and goals.
- Open captions are burned into the video and always showing - this is optimal for customizing the visual styling.
- Closed captions are a separate track that can be turned on or off, depending on the video - this is optimal for working across multiple platforms with different human languages, and are SEO-compatible.
Here are some resources to adding captions to your videos:
- 11 Free Tools to Make Your Video Captioning Process Easier! | Amara.org
- Add your own closed captions - youtube
- Captions and subtitles - vimeo
- Adding Captions in Apple's iMovie
- Caption Video Online - Kapwing
For video on social media such as Instagram, you can type in the captions manually, use the built-in auto-caption tool if available, or burn in captions using a different tool, such as Clipomatic.
How to Test This
If there is video with audio content that requires captioning, check for the presence of captions.
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