Opened 20 months ago

Last modified 9 months ago

#13222 infoneeded_new Bug Report - General

Channel scan with DVB-T2-capable tuner giving bad channel numbers

Reported by: J.Pilk@… Owned by:
Priority: minor Milestone: 30.1
Component: MythTV - General Version: Master Head
Severity: medium Keywords:
Cc: Ticket locked: no


PCTV-290e, current master, fedora 26

qam_64:698000000:BBC ONE E Mid::0:9018:*4166*:4166=4166:dvb       0:cnt(pnum:1,channum:172)                                                                                                                                                                                           
qam_64:698000000:BBC TWO::0:9018:*4287*:4166=4166:dvb     0:cnt(pnum:1,channum:172)                                                                                                                                                                                                   
qam_64:698000000:BBC NEWS::0:9018:*4352*:4166=4166:dvb    0:cnt(pnum:1,channum:172)                                                                                                                                                                                                   
qam_64:698000000:BBC Red Button::0:9018:*4416*:4166=4166:dvb      0:cnt(pnum:1,channum:172)                                                                                                                                                                                           
qam_64:698000000:BBC FOUR::0:9018:*4544*:4166=4166:dvb    0:cnt(pnum:1,channum:172)

The numbers marked above are being displayed instead of the correct ones marked below.

DVB-T-only tuner 

qam_64:698000000:BBC ONE E Mid:*1*:12323:9018:4166:4166=4166:dvb  0:cnt(pnum:1,channum:1)
qam_64:698000000:BBC TWO:*2*:12323:9018:4287:4166=4166:dvb        0:cnt(pnum:1,channum:1)
qam_64:698000000:BBC NEWS:*231*:12323:9018:4352:4166=4166:dvb     0:cnt(pnum:1,channum:1)
qam_64:698000000:BBC Red Button:*250*:12323:9018:4416:4166=4166:dvb       0:cnt(pnum:1,channum:1)              

Attachments (2)

DVB_TuningTest2.txt (15.1 KB) - added by J.Pilk@… 20 months ago.
Part output of "mythtvsetup --verbose channel,chanscan,siparser,record"
DVBTuningTests3.txt (181.5 KB) - added by J.Pilk@… 20 months ago.
Full log of "mythtvsetup --verbose channel,chanscan,siparser,record | tee ~/Documents/DVBTuningTests3.txt"

Download all attachments as: .zip

Change History (9)

comment:1 Changed 20 months ago by Stuart Auchterlonie

Milestone: needs_triage30.0
Status: newinfoneeded_new
Version: UnspecifiedMaster Head

It looks like it's missing the LCN (Logical Channel Number) which is usually signalled in the UK.

Can you grab the output of running

# mythtv-setup --verbose channel,chanscan,siparser,record

it should be sufficient to rescan just the multiplex that broadcasts these channels.

Regards Stuart

Changed 20 months ago by J.Pilk@…

Attachment: DVB_TuningTest2.txt added

Part output of "mythtvsetup --verbose channel,chanscan,siparser,record"

comment:2 Changed 20 months ago by J.Pilk@…

It shot off the top of the screen but here's what looks like the most relevant part. I should be able to capture more if you need it.

The scan was of the main HD mux at 770 MHz. Data for the BBC HD mux for which 9018:4166 apply.

comment:3 Changed 20 months ago by J.Pilk@…

Correction. The data in the attachment refer to the SD mux but were obtained from a scan of the HD mux.

Changed 20 months ago by J.Pilk@…

Attachment: DVBTuningTests3.txt added

Full log of "mythtvsetup --verbose channel,chanscan,siparser,record | tee ~/Documents/DVBTuningTests3.txt"

comment:4 Changed 20 months ago by J.Pilk@…

I don't know if this is significant, but I just scanned with the same device on a 'buntu xenial laptop. Channel numbers were good with 30-pre-438 and 30-pre-484. It's the only tuner on the laptop. I haven't often used it on the Fedora box, where it was 'competing with' an SD tuner. Something might not have been quite right. I think that was 30-pre-484 too. Possibly apologies are appropriate.

comment:5 Changed 20 months ago by J.Pilk@…

Another single-mux scan on the Fedora system, where the two-device setup now seems OK, still gave the bad channel numbers. 30-pre-512, Qt 5.9.4

comment:6 Changed 19 months ago by J.Pilk@…

The laptop from comment 4 is now on 30-pre-556. Yesterday I found that BBC FOUR HD was not working. It seems that the '700 MHz clearance programme' had swapped the muxes on 754 MHz (now QAM-256) and 602 MHz (now QAM-64), and several attempted retunes all gave failed recordings. What eventually worked was deleting both those transports, rescanning with seek-new-linked-transports enabled and scanning yet again on 754 MHz only.

The ubuntu/Fedora channel numbers puzzle persists, but my TV and the Fedora box could both see all the revised muxes without my knowingly having taken special measures during tuning.

comment:7 Changed 9 months ago by Stuart Auchterlonie

Milestone: 30.030.1
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