YouTube live caption preflight checklist

Before going live

• Open the intended Studio broadcast and confirm its title and privacy.
• Verify the encoder sends video to that broadcast.
• Select a compatible latency mode; do not use Ultra low latency for closed captions.
• Turn on Closed captions → POST captions to URL.
• Choose the same subtitle language in Control and Studio.
• Paste that broadcast’s caption URL into Control.
• Choose any Advanced timing adjustment before enabling.

Check the caption path

• Confirm speech reaches StreamTranslate’s live preview.
• Enable the YouTube caption feed.
• Open the matching watch page and turn on CC.
• Compare text with the matching audio in that player.
• Test a short phrase, a long passage and a pause.

When you finish

End the video stream and stop caption audio capture. Verify the relevant controls show offline. Turning off the YouTube caption destination alone is not the same as stopping an active microphone or plugin audio session.

If anything fails

Follow the grey CC button checks or the timing guide. Keep notes about the exact stage that failed. Do not share ingestion URLs or stream keys.

Make the final check reproducible

Use a fixed phrase such as “The next round starts in five minutes,” pause, then say two or three sentences continuously. Confirm the beginning and end appear without old text returning after the pause. Check the selected output language rather than assuming a visible CC label proves the text is correct. If you are testing a translation you cannot read, keep the original transcript and ask someone fluent to review the text before treating it as an accuracy check.

Sources and setup limits

See YouTube’s official requirements for the underlying caption transport and latency modes. Actual behavior must also be checked on your own broadcast.

• YouTube live caption requirements
• YouTube LiveBroadcast API and latency limitations