[mythtv] EIT fix for Czech DVB-S/T

[Petr Stehlik]

Stuart Auchterlonie píše v So 01. 01. 2011 v 21:05 +0000:
> > like the transport ID/network ID mask as a switch. Is it unique at all?
> > How is it working for DVB-T when there are many transmitters - are the
> > TID/NID same across the whole country? How about enabling it per channel
> > somehow so that users can turn it on/off on their own? And how can I
> 
> The TID/NID + service ID is the unique identifier for any given channel.
> Since generally the fixups need to be applied to all EIT data across all
> the channels the TID/NID specifier is sufficient to uniquely identify
> the network (provided they aren't 0).
> 
> EIT data will only be collected for a given channel if
> 1) EIT data is enabled on the data source
> 2) The channel itself is enabled for EIT

Well, my point was that there are about six different sources of Czech
TV channels out there - four different DVB-S providers, one DVB-T and
some DVB-C (not counting IPTV). I don't even know all their TID/NID and
if they weren't compiled in but were configurable at runtime users could
enable/disable the EIT fixes on their own (because I expect all the
sources have common EPG data with the same bugs). My idea is a column in
the 'channel' table that would allow entering the fixup mask.

> > find out where some channel is getting EPG from? Since it seems like for
> > a particular channel it's reading its EIT from a different transport
> > because my EIT fix is not enabled for it.
> 
> EIT data is often "cross-carried". That is, EIT data is broadcast for
> channels which may be on a different mux. This is common in DVB-T but
> not DVB-S.
> 
> Your fixed gets triggered on matching the TID/NID. If your fixup isn't
> being triggered then this must not be matching.

so I basically need to find out the TID/NID of the channel that is
cross-carrying the particular data which is possible by dvbsnooping
only, I guess (I mean it's not documented somewhere and might even
possibly change).

> > Another question is about sharing of EIT data between same channels
> > (same channum, same callsign) of different sources. It seems wasteful to
> > scan for EIT on each card when they are all pointing to the same
> > satellite. If the callsign is same why not share the data for that
> > channel.
> 
> If they all point to the same satellite, then they recieve the same
> channels and should use *1* data source. All cards are considered
> equal in this scenario.

well I have a DVB-S and a DVB-S2 card so the DVB-S2 is receiving all
DVB-S channels plus some -S2 ones. Thus I don't use common data source
for them to indicate that certain stations cannot be tuned on the DVB-S
card.

> If they point to different satellites or recieve different channels
> (for example if you only have a CAM on 1 card) then they should
> use different data sources and will collect EIT data individually.

OK. That didn't work in my tests, unfortunately. Maybe because I was
playing with the various EIT flags in database directly and messed
something up, or perhaps one of the data sources is not tuned correctly
so is missing some information and EIT collecting doesn't work (like if
the channels are imported from the channels.conf).

> There is currently no support for feeding EIT based data across
> to more than one channel.

what a pity. I switched back to feeding the database with
mythfilldatabase manually for each of the three sources - that works
perfectly.

Thanks for your answer.

Petr