Ohio University

Captioning Videos for Web Accessibility

Captions are a text version of the audio of a video. Unlike subtitles, which are typically a straight translation of spoken dialog, captions can and should include other audio elements that are significant to the understanding of the video. Captions can also include notations for who the speaker is and when speakers switch. Caption files are text files with timing added to them. A video player will use this text file and join it with the video. The timing in the caption file is used to show the text on the screen at the appropriate times.

Although YouTube's auto-captions have improved recently, you should not rely on auto-generated captions. For best accuracy you should develop an accurate text transcript of a video, then use a tool or service to synchronize your transcript to the video.

Transcribe and Auto-sync for YouTube

One of the easiest ways to create captions for videos under 5 minutes long is to use the “transcribe and auto-sync” feature within YouTube. This allows you to generate a caption that has appropriate punctuation and capitalization. It also provides you with some control over line breaks which can aid in improving the content of the video. If you are embedding a short video in the OHIO website, you can use this feature to generate the text transcript and then have YouTube automatically time it to create the caption.

With this feature, you start the video, then as you type the video is paused. It automatically resumes playing when you stop typing. When you have generated the full transcript, save it, and YouTube will time your transcript with the video. After that, review the generated caption for any timing and content issues, then publish the transcript. Full details on the Transcribe and Auto-sync feature can be found at YouTube’s website.