[linux-dvb] DVB file formats

Andrew de Quincey adq_dvb at lidskialf.net
Fri Jun 17 12:25:00 CEST 2005


On Friday 17 June 2005 10:51, Andrew de Quincey wrote:
> On Friday 17 June 2005 10:46, Andrew de Quincey wrote:
> > On Friday 17 June 2005 03:50, Andreas Oberritter wrote:
> > > Hi,
> > >
> > > On Fri, 2005-06-17 at 00:10 +0100, Andrew de Quincey wrote:
> > > > The first thing that springs to my mind is something like the
> > > > following:
> > > >
> > > > DVBS: ((frequency / (symbolrate/1000)) << 1) | polarisation
> > > > DVBT: (frequency / bandwidth)
> > > > DVBC: (frequency / symbolrate)
> > >
> > > AFAIK there can not be more than one multiplex one frequency except if
> > > the polarization differs. That makes me think that the divisions are
> > > unnecessary. Instead I'd like to see the orbital position in there for
> > > DVB-S somehow like that:
> >
> > Thats already done - see the GMID in the wiki page.
>
> Oops UMID sorry.

Thought of an issue with this. I was assuming that we would simply give each 
DVBT transmitter its own source_id.. e.g. uk-BlackHill, uk-CrystalPalace.

But the problem is these transmitters are on different frequencies, yet carry 
(some of) the same channels, but we also would want to support sharing of 
presets between them of the channels they do share.

I'm thinking of something like using the full name "uk-BlackHill" say to 
identify a particular transmitter in the services & seeds files.

But in the presets file you just use the "uk" bit to identify the network 
concerned. 

I'm not sure if all countries transmit the same channels on their DVBT 
networks, so you might get clashing IDs. But that is easily resolved:

1) We could use the DVBT multiplex differentiator.
2) You just name the network as well as the country in the source_id - e.g. 
for a hypothetical "other" DVBT network in the uk, you might use 
ukanothernetwork-ATransmitter as the source_id.




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