Nimble Streamer software media server supports WebVTT, SRT, TTML, CEA-608, CEA-708 and DVB closed captioning formats of subtitles for live and VOD output streams.
Closed captions for live streams
Several formats and scenarios are supported with live steaming subtitles. Closed captions can be delivered in NAL units of your content via any live streaming protocol supported by Nimble Streamer.
CEA-608 and CEA-708
These formats of subtitles are supported for MPEG-DASH and HLS as described in this CEA-608/708 article. If your input has those subtitles, your resulting streams will have them once you set it up.
SLDP protocol allows having both CEA-608 and CEA-708 as part of the stream after the same setup.
If your stream has that closed captioning and you want it to survive the transcoding, Nimble Live Transcoder supports subtitles passthrough for that purpose.
DVB subtitles
DVB can be handled the following ways:
- Nimble Streamer can convert DVB subtitles into WebVTT for HLS live streams using image recognition AI.
- DVB teletext can also be converted into WebVTT.
- If your MPEG2TS or HLS stream has DVB subtitles, you can pass them through to output MPEG-TS and HLS.
- Live Transcoder can also pass DVB subtitles through so the resulting stream would have them.
Read Processing Subtitles in Live Streams article for setup details.
Subtitles for VOD HLS and VOD DASH
Nimble supports the following subtitles formats for VOD:
- HLS: WebVTT, SRT and TTML
- MPEG-DASH: WebVTT and TTML
- Both include ABR support via SMIL files
Read this setup article to learn more about VOD subtitles support.
Playout subtitles
Nimble Playout (server playlist) allow inserting WebVTT subtitles alongside with respective VOD files input as part of its generated live stream.
You can also forward those WebVTT through Live Transcoder if needed.