[mythtv-users] scan fails, some old channels no longer "lock" but w-scan sees all channels

Tue May 1 12:52:22 UTC 2018

On Tue, 1 May 2018 13:32:54 +0100, you wrote:

>On 01/05/18 13:14, Alain wrote:
>> Hi,
>> 
>>    On the 24th, the French did something to their emitters and we need 
>> to rescan. TF1 works, but "France 2" fails. The Swiss channels all work.
>> 
>> However, using mythtv-setup, the scan option never detects any channels: 
>> "no new channels found"; even after I delete all channels from the 
>> channel table.
>> 
>> If I run
>> 
>>     w_scan -c CH > /var/tmp/channels.conf
>> 
>> The channels are detected proving that they are there:
>> 
>> C8;NTN:474000:B8D0G8M64T8Y0:T:27500:120=27:0;130,131,132:0;140,141:0:513:8442:2:0
>> BFM TV;NTN:474000:B8D0G8M64T8Y0:T:27500:320=27:0;330:0;340:0:515:8442:2:0
>> CNEWS;NTN:474000:B8D0G8M64T8Y0:T:27500:420=27:0;430:0;440:0:516:8442:2:0
>> CSTAR;NTN:474000:B8D0G8M64T8Y0:T:27500:520=27:0;530,531:0;540,541:0:517:8442:2:0
>> Gulli;NTN:474000:B8D0G8M64T8Y0:T:27500:620=27:0;630,631,632:0;640,641:0:518:8442:2:0
>> France 2;GR1 
>> B:666000:B8D0G8M64T8Y0:T:27500:120=27:0;130,131,132:0;140,142:0:257:8442:1:0
>> France 4;GR1 
>> B:666000:B8D0G8M64T8Y0:T:27500:320=27:0;330,331,332:0;340,342:0:260:8442:1:0
>> France Ô;GR1 
>> B:666000:B8D0G8M64T8Y0:T:27500:520=27:0;530,531:0;540:0:261:8442:1:0
>> franceinfo ;GR1 
>> B:666000:B8D0G8M64T8Y0:T:27500:620=27:0;630:0;640:0:262:8442:1:0
>> F3 
>> Rh?ne-Alpes;FTV:666000:B8D0G8M64T8Y0:T:27500:220=27:230=fre at 3,231=qad,232=qaa:0;240,242:0:282:8442:1:0
>> F3 
>> Alpes;FTV:666000:B8D0G8M64T8Y0:T:27500:720=27:730=fre at 3,731=qad,732=qaa:0;740,742:0:324:8442:1:0
>> M6;Multi4:506000:B8D0G8M64T8Y0:T:27500:120=27:0;130,131,132:0;140,141:0:1025:8442:4:0
>> W9;Multi4:506000:B8D0G8M64T8Y0:T:27500:220=27:0;230,231,232:0;240,241:0:1026:8442:4:0
>> Arte;Multi4:506000:B8D0G8M64T8Y0:T:27500:320=27:0;330,331,332,333:0;340,341,342:0:1031:8442:4:0
>> France 
>> 5;Multi4:506000:B8D0G8M64T8Y0:T:27500:420=27:0;430,431,432:0;440,441:0:1045:8442:4:0
>> 6ter;Multi4:506000:B8D0G8M64T8Y0:T:27500:520=27:0;530,531,532:0;540,541:0:1046:8442:4:0
>> TF1;SMR6:498000:B8D0G8M64T8Y0:T:27500:120=27:0;130,131,132:0;150,151:0:1537:8442:6:0
>> NRJ12;SMR6:498000:B8D0G8M64T8Y0:T:27500:220=27:0;230,231,232:0;250,251:0:1538:8442:6:0
>> TMC;SMR6:498000:B8D0G8M64T8Y0:T:27500:620=27:0;630,631,632:0;650,651:0:1542:8442:6:0
>> TFX;SMR6:498000:B8D0G8M64T8Y0:T:27500:520=27:0;530,531:0;550,551:0:1544:8442:6:0
>> LCP;SMR6:498000:B8D0G8M64T8Y0:T:27500:720=27:0;730:0;750:0:1545:8442:6:0
>> 8_Mont_Blanc;Harmonic:674000:B8D0G32M64T8Y0:T:27500:720=27:730=fra at 3:0:0:2050:8442:8:0
>> LemanBleu HD;LemanBleu 
>> TV:554000:B8:T:27500:516+515=27:517 at 3:518:0:513:0:3841:0
>> SRF 1;Schweizer Radio und 
>> Fernsehen:578000:B8C23D0G4M16T8Y0:T:27500:160=2:80=deu at 3,81=eng:32:0:1:8948:4:0
>> RTS Un;Radio Television 
>> Suisse:578000:B8C23D0G4M16T8Y0:T:27500:161=2:84=fra at 3,85=eng:35:0:257:8948:4:0
>> RTS Deux;Radio Television 
>> Suisse:578000:B8C23D0G4M16T8Y0:T:27500:164=2:96=fra at 3,97=eng:44:0:258:8948:4:0
>> RSI LA 1;Radiotelevisione 
>> svizzera:578000:B8C23D0G4M16T8Y0:T:27500:162=2:88=ita at 3,89=eng:38:0:513:8948:4:0
>> 
>> TF1, NRJ12, RTS* all work fine. But F3 or France 2, can no longer be 
>> seen by mythtv. My real TV is able to pick all those channels, but I did 
>> a rescan on it.
>> 
>>   So mythtv-setup fails to find any channel anymore. I'm including the 
>> logs of mythtv-setup. But I couldn't find anything useful in them.
>> 
>> fixes/29 [v29-rc1-4-g696806310a]
>> All channels seem to be shown with the message "Channel xx offset 1 -- 
>> Timed out, no si...". And then
>>     "Failed to find any new channels!"
>> 
>> However, I can see the Signal Strength bar move to above 50% for some of 
>> those channels.
>> 
>> I've included the log using --loglevel=debug. (Actually had to remove it 
>> to pass the max message size lmit)
>> 
>>    I'm also including a partial log of mythbackend --loglevel=debug when 
>> I try to watch the TV.
>> First I "watched TF1" and that worked, then I changed to "France 2" and 
>> I got the error that it couldn't get a lock.
>> There seems also to be a recording started on another channel (Swiss) 
>> which worked fine.
>> 
>> In the log, look for:
>> 
>> 2018-04-28 17:11:34.363564 I  TVRec[17]: HandleTuning Request: 
>> Program(NULL) channel(2) input() flags(LiveTV,)
>> 2018-04-28 17:11:39.390308 W  TVRec[17]: See 'Tuning timeout' in 
>> mythtv-setup for this input
>> 
>>    Otherwise, most recent version of Ubuntu 17.10.
>> System:    Host: mytv Kernel: 4.13.0-39-generic x86_64 bits: 64 gcc: 
>> 7.2.0 Desktop: Xfce 4.12.3 (Gtk 2.24.31)
>>             Distro: Ubuntu 17.10
>> MythTV Version : v29-rc1-4-g696806310a
>> MythTV Branch : fixes/29
>> Network Protocol : 91
>> Library API : 29.20170212-1
>> QT Version : 5.7.1
>> 
>>     Given that I've been using MythTV for years, this is a bit 
>> frustrating: channel scanning used to work just fine.
>> 
>> Alain Brossard
>
>I'm afraid I'm not familiar with the French TV standards; but I've been 
>having some problems since recent changes in the UK.  Some muxes are on 
>frequencies used earlier but have changed characteristics.  My old habit 
>of updating by scanning 'all known transports' didn't get things right. 
>Have you 'deleted old transports,' or perhaps entered new parameters 
>from an up-to-date listing?
>
>John P

That was my thought too.  The channels you are having problems with
seem to be all on the 666000 MHz multiplex.  So if that used to be on
a different frequency, you may need to either scan that frequency
manually, or do a full scan of all frequencies.  I believe w_scan will
just scan all frequencies, so it found the new frequency.  MythTV will
only scan all frequencies if you tell it to do that, rather than to
scan the existing ones.

This sort of thing may well be better in v30 - I think the code for
scanning is being updated to better conform to the DVB-T standards,
which means that it should find the messages that get sent on one
frequency telling it to scan on a different frequency when things
move.

If you are up for some SQL, this command should show you all the
frequencies for your existing multiplexes:

select mplexid,sourceid,transportid,networkid,frequency from
dtv_multiplex;

If the frequency column does not have any entry where the frequency is
660000000, then your problem channels have moved to a new frequency.