[FFmpeg-devel] [RFC] DVB teletext and PTS

Reimar Döffinger Reimar.Doeffinger at gmx.de
Sat Sep 15 16:29:02 CEST 2012

when specifying PTS handling for DVB teletext they made quite a mess it
seems (see Annex A of ETSI EN 300 472), which resulted in some stations
not using sensible PTS values (for example for ORF the teletext PTS
values seem to indicate a time multiple hours after the video time,
I have a ORF1HD.ts sample here but I don't remember where exactly it
is from).
For ordinary teletext, processing them straight away works fine, but
will completely mess up teletext based subtitles.
This will work for hardware decoders, because at the same time a
"maximum retention time" of 40 ms was specified.
Now the question is: how should we handle this? Would a patch/hack that
limits DVB teletext time stamps to last stream ts + 40 ms be acceptable for
example? It's not really accurate since it should be next ts + 40 ms
though, and quite hacky. But I can't really think of anything better.


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