Live Stream Captions
Streamrun can add automatically generated captions to your live stream in the cloud, between your encoder and the platforms. No caption provider, no encoder plugin, no extra hardware. Deliver them as closed captions viewers can switch on, or burn them into the video so they show everywhere.
Why captions matter
Captions make a live stream accessible to people who cannot hear the audio. They also help when someone is watching with the sound off or following a language that is not their first. Without text, all of those viewers have a harder time following what is happening.
Deaf and hard of hearing viewers
Captions make spoken content accessible. For public events and education, providing them may also be a legal requirement.
Sound-off viewing
People often watch on a phone, at work, or in a public place with the audio muted. Captions let them follow along.
Non-native viewers
Reading along can be easier than following fast speech or an unfamiliar accent. Captions help without requiring a second audio track.
Captions, subtitles, closed and open
The words get used interchangeably, but they mean different things, and the difference decides what your viewers can do with them.
Captions vs subtitles
Subtitles are a translation of what is said, written for viewers who hear the audio but not the language. Captions transcribe the speech in its own language and also describe sounds that matter, such as applause or music, for viewers who cannot hear the audio at all. When you see "[crowd cheers]" on screen, you are looking at captions.
How captions travel
Captions reach a player in one of three ways. Embedded in the video signal as CEA-608 or CEA-708 data, the broadcast standard that live platforms read. As a sidecar file such as WebVTT or SRT, which works for on-demand video but not for a live stream. Or burned into the picture as pixels, which any player can show.
| Closed captions | Open captions (burned in) | |
|---|---|---|
| Delivered as | CEA-708 data embedded in the video stream | Text rendered into the video frames |
| Viewer control | Switched on and off with the CC button | Always visible, cannot be hidden |
| Where they show | Platforms and players that read embedded captions | Every platform, player, clip, and recording |
| Limitation | Invisible on destinations that ignore caption data | Cover part of the picture and cannot be translated by the player |
How live captions get made
Live captions cannot be prepared in advance. There are three common ways to produce them.
Human captioners and caption providers
A stenographer or a captioning service listens to the program and feeds text into the encoder as CEA-608 data. Broadcast television and large conferences work this way.
+ Most accurate, and handles names and jargon.
− Costly per hour, needs booking, and requires an encoder that accepts caption input.
Platform-side automatic captions
Some platforms run speech recognition on the incoming stream and offer captions in their own player.
+ Free and needs no setup.
− Tied to one platform. In a multistream the other destinations get nothing, and you have no control over quality or vocabulary.
Speech recognition in the stream path
A streaming server between the encoder and the platforms transcribes the audio and inserts captions into the outgoing stream, as embedded data or as burned-in text.
+ Automatic, works with any encoder, and reaches every destination at once.
− Accuracy depends on audio quality, accents, and vocabulary, so a noisy venue needs a good microphone.
How Streamrun adds captions
Streamrun runs speech recognition between your encoder and the streaming platforms. Send one stream from any encoder, add the Captions element to your configuration in the Streamrun editor, and every output after it carries the captions. They are added before the stream is split, so they reach all destinations in a multistream with one setting.
Primary language and custom terms
Pick the language you mainly speak as a hint, with bilingual modes for mixed-language streams. Add channel names, guest names, and product names as custom terms so they are spelled right.
CEA-708 closed captions
Embedded in the stream and shown on YouTube, Twitch, and Kick when the viewer presses CC. The video itself stays untouched.
Burned in, multiple lines
A block of text drawn into the picture two lines at a time. Shows on every destination, in clips, and in recordings.
Burned in, word by word
Words appear one at a time as they are recognized, in the style used on short-form video.
Settings and output modes in detail: Captions element documentation.
Frequently asked questions
Does adding captions delay the stream?
Speech recognition runs on the live audio as it passes through, and the video is not held back to wait for it. Captions appear a moment after the words are spoken, the same way they do with a human captioner.
Which platforms show closed captions from a Streamrun stream?
CEA-708 closed captions display on YouTube, Twitch, and Kick, where viewers turn them on with the CC button in the player. For other destinations, or when you want captions to show without a viewer action, use one of the burned-in modes.
Can viewers turn the captions off?
Closed captions, yes. They are a separate track that the player shows or hides. Burned-in captions are part of the picture and cannot be switched off, which is exactly what makes them work everywhere.
Which languages are supported?
Around sixty languages, including English, Spanish, German, French, Portuguese, Japanese, Korean, Mandarin, Hindi, and Arabic, plus bilingual modes for Malay, Mandarin, Tamil, and Tagalog mixed with English. The primary language setting is a hint, so other languages are still recognized when they come up.
Do captions work with OBS, BELABOX, or a phone app?
Yes. Captions are generated in the cloud from the audio in your stream, so any encoder that sends RTMP, SRT, or SRTLA to Streamrun works. Nothing needs to be installed or configured on the sending side.
Do captions reach every destination in a multistream?
Yes. The Captions element sits in the pipeline before the outputs, so every destination downstream of it receives the same captions.
Related
Captions element documentation
Every setting of the Captions element, the supported languages, and the three output modes.
Multi-Platform Streaming
Send one stream to Twitch, YouTube, Kick, and more at once, with captions on all of them.
Live Streaming for Events
Conferences, panels, and ceremonies, where captions are often required and the stream has to stay up.
Live Stream Failover
Keep the broadcast live when a connection or encoder drops, in the same cloud configuration as the captions.
Add captions to your next live stream
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