[mythtv-users] Can't demux Teletext from Channel 4 & Film4

[Nick Morrott]

On 15 February 2010 21:35, Olivier Vogel <vogel.olivier at gmail.com> wrote:
> Hello,
>
> I have a problem with the recordings on Channel 4 and Film4. I can see the
> teletext subtitles when I play the recordings with VLC, but I can't get them
> when demuxing with Project-X.
>
> I don't have this problem with other channels like BBC.
>
> Is anyone having the same problem or does anyone how to solve it?

I had similar problems with recordings from Channel 4/Film4, but in my
case even regular demuxing of the audio and video would fail (audio
stream would sometimes only be present for the first half of the
programme). I'm guessing our two issues may well be connected.

I think the cause of the problems I was seeing was something to do
with PTS changes in the stream during the recording that the 'release'
version of ProjectX does not handle. My best solution to date (that
seems to work for me, but note that I do _not_ demux subtitles) is to
update to a recent SVN version of ProjectX (mine was from a 31/12/2009
checkout).

Special options in PreSettings that I have enabled include:

- global PTS shift = auto
- video: adapt sliding PTSs
- ensure 1st PES-packet starts with video
- generate PCR/SCR from PTS

My initial solution was to demux the audio and video separately using
mplayer and then remux the streams. This did demux the entire audio
stream but there was usually some sync loss.

Not a solution to your specific issue, but I hope this is of interest.

Cheers,
Nick

-- 
Nick Morrott

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