Captions provide a text version of a video’s spoken audio, plus a description of important sounds, synchronized with the video. Typically users can toggle captions on or off using a CC button on their media player. Captions must be available in order to ensure audio content is accessible to people from the Deaf and Hard of Hearing community. They also help people for whom English is a second language, people who process information better if presented in multiple modes (sound and text), people who are unfamiliar with the vocabulary used in the video, people who have the sound turned off on their devices, and people in noisy environments who are unable to hear the sound from their devices. Also, in supporting media players, captions make it possible for users to search the video and can be repurposed as an interactive transcript so users can jump directly to particular points in the video from the transcript text.
Captioning Video Yourself
There are free tools available online that make it possible and easy to caption your own video. Examples include:
The process for creating captions using each tool is approximately the same:
- Upload the video to the web (most services can caption any video as long as it has a public URL, including videos on YouTube). To keep the video private during the captioning process, don’t publish its URL (YouTube offers this as one of its privacy options).
- Provide the video’s URL to the captioning service. Some services also support uploading a video directly to their site.
- Use the service’s captioning tool to watch the video and transcribe it. Caption text is displayed in real-time on the video as you type.
- Review and edit the captions to be sure they’re accurate and easy to follow. The Described and Captioned Media Program (DCMP) provides a Captioning Key with guidelines for effective captioning.
- Download the captions as a caption file in the appropriate format for your needs.
The end product generated by this process is a caption file.
Most caption files are plain text files with time codes indicating the start and stop times for each caption. However, there are various types of caption files with slight variations in their syntax (e.g., SRT, WebVTT, TTML). The type of file you need depends on your media player or video hosting service.
Also, many video hosting platforms provide their own caption editors.
Captions in YouTube
YouTube automatically generates captions for most videos when they’re uploaded. It does so using automatic speech recognition technology, and the captions are rarely accurate enough to be used as an accessibility solution. However, if their accuracy is decent and captions can be perfected with only a few minor corrections, the easiest way to correct them is to do so directly in YouTube. For instructions see YouTube’s help page on how to Edit Captions.
Depending on the accuracy of YouTube’s auto-captions, the length of the video, and other factors, it may be preferable to get the video captioned through other means. The end product will be a caption file, which can be uploaded to YouTube by the video’s account owner. For instructions on how to upload captions, see YouTube’s help page on how to Add your own closed captions.
Captions in Vimeo
Unlike YouTube, Vimeo does not include machine-generated automatic captions. However, they do provide the means for uploading caption files. For instructions on how to upload captions to Vimeo, see Vimeo’s help page on Captions and Subtitles.
Captions in Zoom
For captions in Zoom, see our dedicated Captions in Zoom page.
