Captions
What Are Captions?
Captions are the text version of a video's audio, shown on screen while the video plays. They carry the spoken words, but also the things a viewer would miss without sound: who is speaking, a door slamming, laughter, music starting. Picture a product demo where the presenter says "click the button on the left" while a warning tone sounds. Without captions, a deaf viewer sees a cursor move and hears nothing about the warning at all.
Captions Are Not the Same as Subtitles
Subtitles assume you can hear the audio and just need the words translated into another language. Captions assume you cannot hear it, so they include everything sound was carrying. A file labeled "subtitles" often leaves out speaker names and sound effects, which is why a video can technically have text on screen and still fail an accessibility review.
Closed and Open Captions
Closed captions can be switched on and off by the viewer and are the common choice, because people who do not need them are not forced to read them. Open captions are burned into the video and always visible, which is useful when a platform strips caption files or when video autoplays silently in a social feed.
Auto-Generated Captions and Where They Break
Most platforms will generate captions automatically from speech recognition. They are a starting point, not a finished job. Accuracy drops on names, product terms, accents, crosstalk and anything technical, and the result is often unpunctuated, which changes meaning. A caption that reads "we do not recommend this" as "we now recommend this" is worse than no caption, because the viewer has no way to know it is wrong.
How It Affects Real Users
People who are deaf or hard of hearing rely on captions to use video at all. But the audience is much wider: anyone in an open office without headphones, anyone on a noisy train, anyone watching in a second language, and anyone who simply reads faster than the presenter speaks. Captions also make video searchable, because the text is machine-readable in a way the audio is not.
Where Captions Show Up in an Accessibility Review
A reviewer checks whether pre-recorded video has captions at all, whether they are accurate and synchronized, and whether non-speech audio that matters is included. Live video is judged separately, since real-time captioning is a different obligation. Missing or auto-generated-and-uncorrected captions are among the most common findings on marketing and training pages, precisely because the video looked finished.