The following FAB solutions can be used for subtitling internet video:
- Preparation / export of VTT, Timed Text XML subtitle files for subitling non-live content
- Transmission of subtitles for live video streaming
1. Preparation / export of VTT, Timed Text XML subtitle files for non-live video content
FAB Subtitler STD can be used for preparation of subtitles for video content on the internet. A lowres video file is used for preparation of the subtitle file. The final file can be exported as a VTT file and also in many flavors of Timed Text XML, among others Netflix Timed Text XML, EBU-TT, DFXP TTML, iTunes Timed Text XML and more. The complete list of available export formats is here.
FAB Subtitler PRO can convert subtitle files to any format in an automatic watchfolder mode where subtitle files that have to be converted must only be copied into a folder and the conversion is then done automatically.
2. Transmission of subtitles for live video streaming
FAB Subtitler BCAST/XCD contains the functionality to receive live subtitles from FAB Subtitler LIVE workstations and transmit them in a format necessary for the live video streaming encoder. The live streaming encoder receives subtitles from FAB Subtitler BCAST/XCD and creates an output stream (HLS. MPEG-DASH or similar) with subtitles. Internet video players must then be capable of finding out which subtitle languages are available and allow the viewer to select the apropriate language/subtitle stream and display subtitles overlaid over the video.
The picture below shows the solution for Youtube and live streaming encoders that support the EBU-TT Live protocol over TCP to receive live subtitles over TCP/IP:
The picture below shows the solution for subtitling live streams where subtitles must be present in the SDI video signal as Teletext (OP42/OP47/SMPTE2031) or CEA-608/708 closed captions (i.e. Facebook live video streaming):