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Embedded CEA-608 captions in live streams


We have two applications. MyStream from app1 is pushed to app2 as live stream. We add live captions to MyStream in app2 using OnTextData. Additionally I added a module to convert OnTextData to CEA608 for app2.

What I don’t understand, is what configuration is needed to make these live captions, which are now in live stream as CEA608, available to all for Adobe HDS, RTMP and Apple HLS. The documentation provided gives the impression that if we make captions available as OnTextData then it will work RTMP and HDS, but not with Apple HLS, and if we make them CEA608 it will work with HLS but, not HDS.

You can please elaborate?




if you make captions available as OnTextData then it will work for RTMP and HDS. With ModuleOnTextDataToCEA608 in place the OnTextData should be converted to CEA-608 and that should then be available in the Apple HLS stream for iOS devices. With both of those in place in the same application it should not exclude one or the other. You should be able to see cations in RTMP players such as JW Player, and iOS devices will pick up the CEA-608, as will VLC if given the apple HLS stream’s URL.



With CEA-608, the captions are present in the stream as SEI NAL units, so any code would need to access this to get any of the captions.

Sending the captions as WebVTT might make them more accessible.


iOS devices are able to pick up CEA-608. can we get that caption out and print it in console using any video player or any native iOS code.??