T2 scanning - missing bouqet

[Reiner1210]

Hello,
I think that w_scan2 does not find all channels when scanning T2 (Germany).
I have compared it to Kaffeine (automatic search)

[stefantalpalaru]

Which version and what arguments did you use?

[Reiner1210]

w_scan2 -vvv -a 0 -cDE -ft2 -X -R0 -E0 -O0 -F -t3 > channels_t.conf 2> scan.log
scan.log

Missing:

[Reiner1210]

Next problem:
tzap does not understand the output:
ERROR: error while parsing transmission_mode (syntax error)
TRANSMISSION_MODE_32K is not understand by tzap

[Reiner1210]

Do you need some more informations ?

[stefantalpalaru]

I can't figure out what the scanning problem is, because I don't see any clue in the logs.

As for the tzap problem, it's known since at least 2018:

"Since the newer dvb-t2 channels would need 32K then tzap won't work - too old as it only appears to support 2K or 8K." - https://www.linuxquestions.org/questions/linux-software-2/scan-tune-to-dvb-t2-tv-at-the-command-line-4175644365/#post5940330

You can probably replace "TRANSMISSION_MODE_32K" with "TRANSMISSION_MODE_AUTO", to let tzap parse it, but a better solution is to move to dvbv5-zap.

[Reiner1210]

Yes this was I have done.
Scanning problem: I have tried it with 2 sticks (Haupauge Dual and Sundtek)
Kaffeine works with Haupauge stick and finds all channels - what do they use ?

[stefantalpalaru]

what do they use ?

https://invent.kde.org/multimedia/kaffeine/-/blob/master/src/dvb/dvbscan.cpp?ref_type=heads

[Reiner1210]

```cpp // Seek for DVB-T2 transponders

if ((autoScanSource == QLatin1String("AUTO-T2-Normal")) ||
	   (autoScanSource == QLatin1String("AUTO-T2-Offsets"))) {
	bool offsets = (autoScanSource == QLatin1String("AUTO-T2-Offsets"));

	for (int frequency = 177500000; frequency <= 226500000; frequency += 7000000) {
		DvbTransponder currentTransponder(DvbTransponderBase::DvbT2);
		DvbT2Transponder *dvbT2Transponder = currentTransponder.as<DvbT2Transponder>();
		dvbT2Transponder->frequency = frequency;
		dvbT2Transponder->bandwidth = DvbT2Transponder::Bandwidth7MHz;
		dvbT2Transponder->modulation = DvbT2Transponder::ModulationAuto;
		dvbT2Transponder->fecRateHigh = DvbT2Transponder::FecAuto;
		dvbT2Transponder->fecRateLow = DvbT2Transponder::FecNone;
		dvbT2Transponder->transmissionMode = DvbT2Transponder::TransmissionModeAuto;
		dvbT2Transponder->guardInterval = DvbT2Transponder::GuardIntervalAuto;
		dvbT2Transponder->hierarchy = DvbT2Transponder::HierarchyNone;
		dvbT2Transponder->streamId = 0;
		transponders.append(currentTransponder);
	}

	for (int frequency = 474000000; frequency <= 858000000; frequency += 8000000) {
		for (int i = 0; i < 3; ++i) {
			if ((i != 0) && (!offsets)) {
				break;
			}

			int offset = 0;

			if (i == 1) {
				offset = -167000;
			} else if (i == 2) {
				offset = 167000;
			}

			DvbTransponder currentTransponder(DvbTransponderBase::DvbT2);
			DvbT2Transponder *dvbT2Transponder = currentTransponder.as<DvbT2Transponder>();
			dvbT2Transponder->frequency = frequency + offset;
			dvbT2Transponder->bandwidth = DvbT2Transponder::Bandwidth8MHz;
			dvbT2Transponder->modulation = DvbT2Transponder::ModulationAuto;
			dvbT2Transponder->fecRateHigh = DvbT2Transponder::FecAuto;
			dvbT2Transponder->fecRateLow = DvbT2Transponder::FecNone;
			dvbT2Transponder->transmissionMode = DvbT2Transponder::TransmissionModeAuto;
			dvbT2Transponder->guardInterval = DvbT2Transponder::GuardIntervalAuto;
			dvbT2Transponder->hierarchy = DvbT2Transponder::HierarchyNone;
			dvbT2Transponder->streamId = 0;
			transponders.append(currentTransponder);
		}
	}

</code>

[Reiner1210]

So the missing stuff will be found from the 2. loop - without offset.
Where are your loops ? Can't see them quickly

[stefantalpalaru]

This is the transponder tuning function:

w_scan2/src/scan.c

Line 2543 in 212f116

__tune_to_transponder(int frontend_fd, struct transponder *t, int v)

[Reiner1210]

Ok and from where do you get the frequencies ?

[stefantalpalaru]

w_scan2/src/scan.c

Line 2886 in 212f116

initial_tune(int frontend_fd, int tuning_data)

[Reiner1210]

In my logfile I found the following

parse_T2_delivery_system_descriptor:1367 f578000 system_id7766 plp_id1 SISO/MISO=SISO B8.0 G19128 T16 other_frequency1 TFS0
1 cells:
cell 577: center_frequency 578.000
find_transponder(8468:12352:16498): -> not found.
find_transponder_by_freq(QAM_AUTO f = 578000 kHz I999B8C999D0T16G19128Y0P1 (8468:12352:16498)) -> not found. (line 585)
find_transponder_by_freq(QAM_AUTO f = 578000 kHz I999B8C999D0T16G19128Y0P1 (8468:12352:16498)) -> not found. (line 585)
new transponder: (QAM_AUTO f = 578000 kHz I999B8C999D0T16G19128Y0P1 (8468:12352:16498)) 0x4004
cell577: center_frequency578000000


578000 is the frequency !

later:

578000: skipped (already known transponder)

[stefantalpalaru]

That's the part where it gets new transponder frequencies from old ones. Plenty of duplicates there.

What we need is the part where it tunes to that specific frequency and fails to get a lock, after the timeout:

tune to: QAM_AUTO f = 578000 kHz I999B8C999D0T16G19128Y0P1 (8468:12352:16498) (time: 02:43.949) 
 (0.356sec): SC 
 (1.026sec):  
 (1.332sec): SC 
 (1.996sec):  
 (2.302sec): SC 
 (2.947sec):  
 (3.252sec): SC 
----------no signal----------
tune to: QAM_AUTO f = 578000 kHz I999B8C999D0T999G999Y0P1 (8468:12352:16498) (time: 02:47.814)  (no signal)
 (0.407sec): SC 
 (1.003sec):  
 (1.361sec): SC 
 (1.973sec):  
 (2.126sec): SC 
 (2.921sec):  
 (3.074sec): SC 
 (3.891sec):  
----------no signal----------
        find_transponder_by_freq(QAM_AUTO f = 578000 kHz I999B8C999D0T999G999Y0P1 (8468:12352:16498))             matches tn center

[stefantalpalaru]

w_scan2/src/scan.c

Lines 2577 to 2579 in 212f116

	ret & FE_HAS_SIGNAL ? "S" : "",
	ret & FE_HAS_CARRIER ? "C" : "",
	ret & FE_HAS_LOCK ? "L" : "");

So "SC" means we have a signal and carrier, but no lock.

[Reiner1210]

By the way: Which format must be chossen to use dvbv5-zap instead of tzap ?

[stefantalpalaru]

Which format must be chossen to use dvbv5-zap instead of tzap ?

Both use the same format.

[Reiner1210]

Don't think so
dvbv5-zap -c channels_t2.conf zdf
Demultiplexer »dvb0.demux0« wird verwendet.
Kanäle werden aus Datei »channels_t2.conf« gelesen.
FEHLER Schlüssel/Wert ohne eine Kanalgruppe beim Auswerten der Zeile 1 von channels_t2.conf

[stefantalpalaru]

You need to add "-I ZAP" to its command line.