StreamTranslateOpen the broadcast receiving your video
In YouTube Studio’s Live Control Room, open the broadcast you will actually stream to. Check its title and privacy. A saved stream key can be associated with multiple broadcasts, so another open Studio tab is not proof that you selected the right one.
Copy the caption destination
- Open Stream settings.
- Turn on Closed captions.
- Choose POST captions to URL as the captions source.
- Select the caption language.
- Copy Captions ingestion URL into Control → YouTube CC.
This URL is separate from the RTMP/RTMPS video server and stream key. Do not paste a watch-page URL into the caption field.
Do you need a new URL after changing language?
In our private-broadcast Studio check, selecting Japanese, Chinese, Arabic, French, Spanish and English kept the same captions URL. That result covers that tested broadcast. Compare Studio’s current URL when changing broadcasts or stream-key settings; if it differs, replace the saved destination.
Disabling and re-enabling captions in the same Control page retains your pasted URL. A page reload clears the input so you can check the destination for the next session.
Keep the destination private
The caption URL contains credentials for sending captions. Keep it out of screenshots, public chat, repositories and support posts. Share a screenshot with the field masked if you need help.
Keep a safe connection checklist
Before each stream, compare the broadcast title and the encoder destination, then check the current caption URL in that broadcast. Keep the value only in the caption field or an appropriate secret store. If you need to compare URLs for troubleshooting, compare them privately; a masked screenshot of the settings is safer than pasting the whole value into a public help thread. Do not assume the caption URL from another event remains the correct destination just because your channel has not changed.
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.
Common questions
Is this the YouTube stream key?
No. The stream key sends the video stream. The captions ingestion URL accepts a separate caption feed.
Why can captions go missing even after enabling?
One possible cause is pairing one broadcast’s caption URL with a different broadcast’s video. Check the live broadcast and its watch link first.