Two caption streams, CEA608 and WebVTT in HLS

Wowza Streaming Engine
1

My live application is accepting an RTMP input video stream that contains onTextData captions in a single language. The output of the app is 3 transrated HLS streams, using a SMIL file to create WebVTT captions so the JWPlayer shows the correct language name on the CC menu.

We also Push Publish the stream from this App to Facebook Live, which requires CEA608 captions. We have therefore also enabled the module “ModuleOnTextDataToCEA608”.

This all works as it should; Facebook Live gets the captions ok, and the JW player also gets the WebVTT captions and displays “English” in the CC menu, as it should.

However, the CEA 608 captions are also in the HLS streams and JW player adds “Unknown CC” to the CC menu when it sees them in the stream.

Question: Is it possible to keep the CEA608 captions in the Push Publish RTMP stream to Facebook Live but specify NOT to put them into the transrated HLS streams?

2

I checked with our engineers @David Boniface and the response was you can only push the CEA608 captions to FB Live but not to the HLS streams. I’m sorry for any inconvenience this may cause you.

We are checking on a method for you to use for the transrated streams and I will respond again shortly. Thanks for your patience.

3

I have the opposite problem. The CEA608 captions are in both output streams, the RTMP and the transrated HLS streams.

Since I also have WebVTT captions for the HLS streams, I want to be able to kill the CEA608 captions in the HLS streams., but leave them in the RTMP stream.

4

Here is the solution to turn them off in the HLS streams:

https://www.wowza.com/docs/how-to-turn-off-the-alternate-track-button-in-apple-ios-devices

Does this resolve your need? Please let me know.

5

Rose,

That does partially work. That is, it does add the CLOSED-CAPTION=NONE to the playlist’s EXT-X-STREAM-INF line. However JW Player seems to ignore it.

I would prefer a solution that prevents the CEA608 data being in the HLS stream, but I think this is the best I can do in the Wowza realm.

I think I have to visit JW Player now and persuade them to honor the setting in the playlist.

Thank you for your help.

6

Interesting…I’ll double check for you if we have any other approach you could try. Thanks for the great communication.