Destinations
Once captions are generated, they need to be sent to a destination for them to be displayed for the audience. Line 21 supports 5 categories of destinations:
| Category | Text | Video | Languages | Description |
|---|---|---|---|---|
| Browser | All | A sharable browser page that displays captions. | ||
| Overlay | All | A floating, borderless window that display captions on top of other content or applications. | ||
| Text Destinations | All | API-based delivery of captions as text to various target platforms, systems, apps, pages | ||
| RTMP Streaming | Single | Encoding captions into a RTMP video and simulcast it to Facebook, Twitch, Twitter or YouTube. | ||
| HLS Streaming | All | Publish video and captions to an HLS video player, embeddable in your own website or standalone. |
Last updated: January 13, 2026 at 09:22 AM