[linux-dvb] Re: VDR 0.92 : No more EIT on Canal Satellite

[Klaus Schmidinger <Klaus.Schmidinger@cadsoft.de>]

Jean-Claude Repetto wrote:
> 
> ----- Original Message -----
> From: "Klaus Schmidinger" <Klaus.Schmidinger@cadsoft.de>
> To: "Rolf Hakenes" <hakenes@hippomi.de>
> Cc: <jrepetto@mxmlab.com>
> Sent: Tuesday, August 21, 2001 12:25 AM
> Subject: Re: [linux-dvb] VDR 0.92 : No more EIT on Canal Satellite
> 
> > Rolf Hakenes wrote:
> > >
> > > > -----Ursprüngliche Nachricht-----
> > > > Von: Jean-Claude REPETTO [mailto:jrepetto@francenet.fr]
> > > > Gesendet: Sonntag, 19. August 2001 21:53
> > > > An: linux-dvb@linuxtv.org
> > > > Betreff: [linux-dvb] VDR 0.92 : No more EIT on Canal Satellite
> > > >
> > > >
> > > > I have noticed a small problem on the french channels of
> > > > Canal Satellite on
> > > > Astra. The current and next program aren't displayed anymore.
> > > > I suppose it
> > > > is related to the changes in the EIT processing. I haven't
> > > > them with DTV
> > > > either.
> > > >
> > > > Jean-Claude
> > > >
> > > Hi again,
> > >
> > > unfortunately the problem is not that small. It is caused by wrong
> time-stamps
> > > for the EPG data the CANALSATTELITE channels deliver. I have checked
> this here,
> > > the information is existent, but always in the future, therefore it is
> not
> > > possible to get a 'present' (and no 'following') broadcasting by
> analysing the
> > > time, as Klaus has to do since he uses my library. There are two
> possibilities
> > > to fix this,
> >
> > Well, actually there's a third one: they could adhere to the standard!!
> > Gee, I hate to fiddle around to fix stuff that was intentionally broken.
> >
> > > either to re-introduce the 'present-following' flag to the
> > > EPG-data, as I supposed to Klaus some mails earlier (with all the
> drawbacks that
> > > means), or to correct the time-stamp of the EPG. I would prefer the
> second
> > > choice, as only this enables using the recording feature in the correct
> way. I
> > > remember some discussions a long time ago concerning wrong TDT
> time-stamps of
> > > some channels (maybe Klaus knows more exactly about that, I am not sure
> whether
> > > these are the same channels), possibly a correction of the stamps is
> possible
> > > while using these TDT messages...
> >
> > This is getting more and more annoying. First Pro7 with their wrong date
> on events
> > between 00:00 and 06:00, now some French and Spanish channels who are
> unable to
> > send the timestamps in UTC - what's next?
> >
> > If it just were that easy to identify a specific channel, but as has been
> posted
> > in several messages here, the service ID is by no means unique, and using
> the
> > channel name is also pretty unreliable, because not everybody wants to
> name the channels
> > the same way.
> >
> > Isn't there _some_ bit in the EIT data stream indicating that the
> timestamps are
> > in local time instead of UTC? Maybe that's what Rolf was suggesting above:
> if
> > libdtv realizes that an event which is marked as "present" has a timestamp
> that
> > is more than, say, 30 minutes in the future, it could assume that all
> events
> > from this service ID have wrong timestamps and shift them by the
> difference
> > between the "present" event and the current time?
> >
> > Of course this would only be curing the symptoms. The real solution would
> be
> > if those braindead idiots would send the correct timestamp in the first
> place...
> >
> > Klaus
> > --
> 
> I have asked on french sat forums, and it appears that commercial receivers
> (Nokia 9800S, XSAT CDTV310VM , ASTON 1600 ...) display the wrong time on
> Canal Satellite channels.
> I'll have a look at the EIT data stream to see if there is a bit indicating
> that it is UTC or local time, but it won't help, since the local time is
> unknown.
> So I would suggest to add an optional time zone field in channels.conf, only
> for the channels that are not in UTC, then to correct the time according to
> the time zone.
> For example, all Canal Satellite channels in local time would have a
> "Europe/Paris" time zone.
> 
> What do you think about that ?
> 
> Jean-Claude

You want my honest opinion? Well: I hate it!
This would be a field that has no meaning for most channels,
but every user who programs a channel would be confronted with it
and maybe wondering what he/she has to enter here.

A workaround like this should be done in a way that it can be easily
dropped once the actual bug is fixed (i.e. the tv stations finally
learn how to follow the standard) and does not irritate users who
don't view these channels.

If you take a look at VDR's eit.c, you can see that I have done some
time correction for Pro7 and Kabel1, since these guys apparently also can't
work a clock and calendar. Maybe a similar thing can be done there for
the French channels. Note, though, that at this point all you have to identify
the station is the EIT data (i.e. primarily the ServiceID, which may not be
unique - I don't know what other EIT info could be used to clearly identify
a station).

Since even commercial STBs show the wrong times I would assume that
sooner or later these stations will have to transmit times as UTC.

Klaus
-- 
_______________________________________________________________

Klaus Schmidinger                       Phone: +49-8635-6989-10
CadSoft Computer GmbH                   Fax:   +49-8635-6989-40
Hofmark 2                               Email:   kls@cadsoft.de
D-84568 Pleiskirchen, Germany           URL:     www.cadsoft.de
_______________________________________________________________


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