You can make sure that your live broadcasts are as accessible as possible to all your viewers by adding captions to your live videos. Displaying subtitles and text tracks on your live video lets you control the accuracy of your messaging and allows you to reach a wider audience, including those who rely on text to watch videos. This improves accessibility and comprehension for the entirety of your audience. In addition, subtitles empower your viewers to digest the message in whichever way is best for them, be it audio, text, or a combination.
Captions in the live video will be saved in the archived version of the video so that your viewers can return and watch key moments with captioning.
To allow us to display captions on your live video, you need to provide us with an RTMP video source that contains captions. This can be done through a number of ways:
- Use our Livestream Studio software with an SDI input that contains captions.
- Other software or encoder plugins to generate captions on your content.
- A third-party live captioning provider to enrich the RTMP signal with captions prior to inputting it into the platform.
From a more technical perspective, we will decode captioning data on the same line that's used in the CEA-608 standard. We only support decoding one captioned language to display. We display a different standard to our player (WebVTT) and this does not support some functionality like scrolling, wipes, and positioning within the video frame, which are common in broadcast and TV standards. It should also be noted that we only support captions for live video in the web player, and not in our mobile apps or on our Enterprise HLS/m3u8 output.
Once you end the stream, the resulting video will have a captioned file that's available for download from the video settings page (under Distribution). You can also replace this file if the captions contain an error as well as upload additional files to display multiple languages, just as you would for an uploaded video.
We encourage you to test out your workflow prior to your event; you can do this by creating an event and set the privacy to "Only me." Be sure to check them on the video's clip page (i.e. what your viewers would see), as captions do not appear in the live preview page (where you would typically configure and monitor your event).