What are the caption file types?

You can upload multiple subtitle and caption files (SRT, DXFP, XML) and transcripts (TXT), or reference an external link to a captions file in the KMC. Viewers can then select and toggle between different language subtitles and captions. Subtitles and captions are fully searchable as a metadata field.

For more information see the Kaltura captions search demo.
You can also automate the creation of subtitles and captions, and transcriptions through our partners in Kaltura Exchange. See an example here.

Closed Captioning for Adaptive Bitrate Streaming with Wowza Streaming Engine

Wowza Streaming EngineTM integrates closed captioning into streaming video content, making online video accessible to a broader audience and allowing publishers to comply with the FCC’s 21st Century Communication and Video Accessibility Act (CVAA) of 2010. The CVAA requires that people with disabilities such as hearing loss have access to video content delivered over the Internet, whether it’s viewed on a computer or a mobile device.

Just as there are a number of protocols, formats, and playback devices for streaming video, so too are there a number types of closed caption formats. And each adaptive bitrate streaming standard, whether HDS, HLS, or RMTP, supports different formats for embedded captions in streamed video. The good news is that Wowza Streaming Engine provides the widest range of supported caption formats and caption conversion capabilities of any media server for live and video on-demand (VOD) content. Wowza Streaming Engine even lets you include captions in multiple languages.

Closed Captions for Live Streams

For inbound live content, Wowza Streaming Engine accepts instream (embedded) CEA-608 captions (sometimes called Line 21 captioning), the format used by traditional broadcast TV. Through its Java API, Wowza Streaming Engine can also connect to back-end caption providers, allowing the engine to ingest virtually any live caption format. WSE also accepts AMF onTextData and AMF onCaption caption events in live streams.

For outbound video, Wowza Streaming Engine directly embeds CEA-608 or WebVTT captions in live streams played back via Apple HLS. For live events streamed via Adobe HDS or RTMP, Wowza Streaming Engine displays captions using onTextData events.

Closed Captions for VOD

For on-demand content, Wowza Streaming Engine can convert and deliver captions that are embedded in the video content as well as captions that are delivered in external files alongside the video content, sometimes called sidecar files. Wowza Streaming Engine can extract 3GPP Timed Text caption data from MP4 files or from companion files that use Timed Text Markup Language (TTML), SubRip Text (SRT), WebVTT, or Scenarist Closed Caption (SCC) formats to specify caption data. This caption data can be injected into Apple HLS streams as CEA-608 or WebVTT captions or into Adobe HDS and RTMP streams as onTextData events.

Caption Input Format

See more at: http://www.wowza.com/products/streaming-engine/features/closed-captioning#sthash.RL06vRQn.dpuf