DVB-S/T Teletext Subtitles doesn't follow PTS

[StephaneM]

Hello,

 

It seems to me that Teletext Subtitles contained in DVB-T/S Transport Streams are presented immediately when they should be displayed only respective to their PTS (if given).

 

So on all my recordings tests, TTX subs are shown 2 secs early. I made a small program to verify the TS stream and if I observe the PTS of the TTX packets I got the right synch always (I currently extracted the TTX subs to a smi file and verified that the synch was ok).

 

I guess that when the TTX packets carry a PTS, then the PTS must be observed, but when TTX packets doesn't have a PTS, they should be displayed right away (within a 40ms tolerance). I guess DVBViewer always display the TTX subs right away even when the PES packets cary a valid PTS.

 

Regards,

Stéphane.