Building inclusive technology is core to the Cloudflare mission. Cloudflare Stream has supported captions for on-demand videos for several years. Soon, Stream will auto-detect embedded captions and include it in the live stream delivered to your viewers.
Thousands of Cloudflare customers use the Stream product to build video functionality into their apps. With live caption support, Stream customers can better serve their users with a more comprehensive viewing experience.
Enabling Closed Captions in Stream Live
Stream Live scans for CEA-608 and CEA-708 captions in incoming live streams ingested via SRT and RTMPS. Assuming the live streams you are pushing to Cloudflare Stream contain captions, you don’t have to do anything further: the captions will simply get included in the manifest file.
If you are using the Stream Player, these captions will be rendered by the Stream Player. If you are using your own player, you simply have to configure your player to display captions.
Currently, Stream Live supports captions for a single language during the live event. While the support for captions is limited to one language during the live stream, you can upload captions for multiple languages once the event completes and the live event becomes an on-demand video.
What is CEA-608 and CEA-708?
When captions were first introduced in 1973, they were open captions. This means the captions were literally overlaid on top of the picture in the video and therefore, could not be turned off. In 1982, we saw the introduction of closed captions during live television. Captions were no longer imprinted on the video and were instead passed via a separate feed and rendered on the video by the television set.
CEA-608 (also known as Line 21) and CEA-708 are well-established standards used to transmit captions. CEA-708 is a modern iteration of CEA-608, offering support for nearly every language and text positioning–something not supported with CEA-608.
Live caption support will be available in closed beta next month. To request access, sign up for the closed beta.
Including captions in any video stream is critical to making your content more accessible. For example, the majority of live events are watched on mute and thereby, increasing the value of captions. While Stream Live does not generate live captions yet, we plan to build support for automatic live captions in the future.