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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 teletext.

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 teletext to SDI, specify numbers of the lines where you allocate the teletext in the output stream:

stream out {
  url file://vod/mpegts.ts;
  push decklink://1 deinterlace=false 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 teletext. 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.