Re: French DVB-T Channel IDs vs. EIT Channel IDs

On 09.03.2018 11:51, Patrick Boettcher wrote:
> On Fri, 9 Mar 2018 11:30:36 +0100
> Klaus Schmidinger <[email protected]> wrote:
> 
>> On 01.03.2018 10:22, Patrick Boettcher wrote:
>> > On Wed, 28 Feb 2018 11:01:23 +0100
>> > Klaus Schmidinger <[email protected]> wrote:
>> >   
>> >> On 27.02.2018 17:58, Patrick Boettcher wrote:  
>> >> > On Tue, 27 Feb 2018 16:54:35 +0100
>> >> > Klaus Schmidinger <[email protected]> wrote:
>> >> >     
>> >> >> Hello Patrick,
>> >> >> 
>> >> >> your scan doesn't contain the NIT, which is where the
>> >> >> transponder innformation is broadcast. Can you scan that, too,
>> >> >> please?    
>> >> > 
>> >> > Hi Klaus,
>> >> > 
>> >> > NIT attached (from another multiplex with the same symptoms).    
>> >> 
>> >>              DVB-DescriptorTag: 90 (0x5a)  [=
>> >> terrestrial_delivery_system_descriptor] descriptor_length: 11
>> >> (0x0b) Center frequency: 0xffffffff (= 42949672.095 kHz)
>> >> 
>> >> @@ -219,6 +219,8 @@
>> >>                    cDvbTransponderParameters dtp;
>> >>                    int Source = cSource::FromData(cSource::stTerr);
>> >>                    int Frequency = Frequencies[0] =
>> >> sd->getFrequency() * 10;
>> >> +                 Frequency = Transponder() * 1000000;//XXX
>> >> +                 dsyslog("Frequency = %08X, Transponder = %d",
>> >> sd->getFrequency(), Transponder());//XXX static int Bandwidths[] =
>> >> { 8000000, 7000000, 6000000, 5000000, 0, 0, 0, 0 };
>> >> dtp.SetBandwidth(Bandwidths[sd->getBandwidth()]); static int
>> >> Constellations[] = { QPSK, QAM_16, QAM_64, QAM_AUTO };  
>> > 
>> > It works. I had to have VDR recreate the channels because it was
>> > mixing things up with the already existing ones.
>> > 
>> > As to why the frequency is set to "-10" I don't know (yet), but I
>> > remember it has always been like this since 2005.
>> > 
>> > Initial tuning files have always contained all active frequencies
>> > for their region, because the NIT did not set the center frequencies
>> > correctly.
>> > 
>> > It might be because the multiplexed transport streams are generated
>> > centrally and then distributed to all the base-stations where they
>> > are emitted as-is but on different frequencies depending on the
>> > region.
>> > 
>> > What can we do to get this upstream?  
>> 
>> I'm afraid I don't see how this case can be handled correctly.
>> 
>> Maybe somebody else has an idea?
> 
> One approach might be to ignore frequencies for DVB-T channels update
> during NIT parsing (in France only?).
> 
>>From my experiences with DVB-T SetTopBoxes using the NIT for
> new channel-discovery is rarely done. No customer of my ex-employer was
> using it - scanning was entirely based on continuous frequency-band
> scanning with a spare demod.
> 
> That would be my idea. But I don't know whether this can be easily
> applied to VDR.

Well, maybe this works for you?

--- nit.c       2016/12/23 14:16:59     4.4
+++ nit.c       2018/03/09 10:53:38
@@ -218,6 +218,8 @@
                   SI::TerrestrialDeliverySystemDescriptor *sd = (SI::TerrestrialDeliverySystemDescriptor *)d;
                   cDvbTransponderParameters dtp;
                   int Source = cSource::FromData(cSource::stTerr);
+                 if (sd->getFrequency() == 0xFFFFFFFF)
+                    continue;
                   int Frequency = Frequencies[0] = sd->getFrequency() * 10;
                   static int Bandwidths[] = { 8000000, 7000000, 6000000, 5000000, 0, 0, 0, 0 };
                   dtp.SetBandwidth(Bandwidths[sd->getBandwidth()]);

Klaus

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