Anyone who has watched a foreign film with subtitles has an intuitive sense of what live event captioning does. But putting real-time text on a stage screen, in front of a live audience, with a speaker who does not pause, edit, or repeat themselves, is a different technical challenge entirely.
Subtitling vs surtitling: not quite the same thing
The two terms get used almost interchangeably, but there is a real distinction worth knowing if you are organizing an event.
Subtitling typically refers to text displayed at the bottom of a screen, layered over existing video content. Think a translated interview or a video clip played during a keynote.
Surtitling, by contrast, refers to text displayed above or alongside a live performance or presentation. It is the format most commonly used for opera, theatre, and live conference stages, where there is no underlying video to caption, just a speaker in real time. Surtitles are typically shown on a separate screen or projected above the stage, rather than burned into a video feed.
For most conferences and corporate events, what is needed is closer to live surtitling: real-time, speaker-following text, shown on a screen the whole room can see, generated as the words are spoken, not added afterward in post-production.
Where chroma key comes in
For events that want captions integrated directly into a broadcast or livestream feed, rather than displayed on a separate screen, chroma key technology (the green screen technique used across broadcast and film) becomes relevant. A captions layer can be composited onto a chroma-keyed background and mixed live into the video output, so remote viewers watching a stream see captions embedded directly in the broadcast, exactly where the production team wants them, without a separate on-site screen.
This matters for hybrid events in particular, where part of the audience is in the room and part is watching remotely. The in-room audience might see captions on a stage screen, while the livestream audience sees them composited into the video feed: two different technical paths delivering the same accessibility outcome.
The role of the régie
None of this happens without a control room, what is referred to in French production terminology as the régie. This is the technical nerve center of any live event: the point where video feeds, audio, lighting, and now caption or subtitle streams all get mixed and routed to their final destination, whether that is the stage screen, the livestream, or both.
Integrating live captions into a régie workflow means the captioning system needs to output a clean, low-latency feed that the technical team can route like any other video or graphics source. No manual copy-pasting, no separate laptop balanced backstage, no risk of the captions falling out of sync with what is actually being said on stage.
Where Glot fits into this workflow
Glot is built to slot directly into this kind of production environment. Whether an organizer wants captions displayed on a dedicated screen for the in-room audience, a caption feed integrated into the régie for a livestream or recorded broadcast, or both running in sync in multiple languages at once, the underlying transcription and translation engine is the same. What changes is simply where the output is routed.
That flexibility is what makes captioning practical across very different event formats: a single-stage conference, a multi-track summit with several control rooms, or a hybrid event streaming to a remote audience across time zones.
Why this matters more than most organizers realize
Live captions on the big screen are not just an accessibility feature for hard-of-hearing attendees, although that alone justifies the investment. They also help international guests follow a language they are still learning, help attendees in a noisy hall stay engaged when audio is hard to hear, and give remote viewers watching a livestream the same clarity as someone sitting in the front row.
Done well, captioning becomes invisible. The audience simply understands the event, without thinking about the technology making that possible.
Planning a conference and want captions integrated into your screen or régie setup?
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