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Passing teletext from MPEG-TS to analog streams

Flussonic Media Server can pass teletext from MPEG-TS to analog streams in SD quality that are broadcast via Decklink SDI cards. Teletext is added to VBI (vertical blanking interval) of an output stream, and you will need to specify numbers of VBI lines that will carry the teletext track.

Prerequisites:

  • An input MPEG-TS stream containing Teletext B.
  • An output stream containing SD video that Flussonic will transmit to a Descklink SDI card.

To pass a teletext track to SDI, specify numbers of the lines where the teletext in the output stream will be packed:

stream out {
  url file://vod/mpegts.ts;
  push decklink://1 format=pal vbi=ttxt:7:8:9:319:320:321;
}

In the example, the vbi option specifies six figures separated by colons — these are numbers of VBI lines that will carry a teletext track. The first three are VBI lines passed in the first half-frame and the next three figures are lines in the second half-frame.

If the teletext in your stream does not fit into the specified lines, it will not appear in the output stream. In this case, specify more lines in vbi.