[mythtv-users] UK Freeview scanning broken?

[John Pilkington]

On 24/03/17 08:59, Justin Hornsby wrote:
> Which transmitter?
>
> Pontop Pike.
>
>
> I'll explain what I did in full then:
>
> First of all I did what I usually do which is a full scan of existing
> transports. This found as many channels as I'd expect - it seemed very
> happy & I went to exit out of mythtv-setup which then said TV on my
> tuners was set to start on channel 1, which doesn't exist - was I sure I
> wanted to quit?
>
> Hmm normally I might use the 'no, I know what I'm doing' option but
> channel 1 not existing rang alarm bells so I went into the channel
> editor again.  None of the LCNs seemed to be correct.  Uh-oh.
>
> So, I then did a full scan (tuned) to the frequency of the BBC mux.
> This time it only pulled in BBC channels and yet again the LCNs were all
> massively wrong.
>
> It was then I thought ah what the heck & deleted all the channels & then
> did a tuned scan - this time having selected the 'use other transports'
> tickbox.  Same result - all the LCNs massively messed up.
>
> By this point I was feeling frustrated so thought right!  I'll delete
> all the channels & all the transports & do a full scan.  I had nothing
> to lose.  And yet again, it pulled in all the channels I'd expect to see
> but the channel numbers were wildly wrong.
>
> I rescanned my TV at the same time - it found changes & updated itself
> pretty quickly.  All its channel numbers are fine.  Oh dear oh dear.
>
> So it looks very much like mythtv's scanner isn't working quite right,
> or else the transmitter is putting out something that mythtv doesn't
> know about but my 2 year old TV is fine with.
>
> The 'scan' util always works fine & is very quick... I even did a w_scan
> (ugh) & it also worked - and appeared to squirt out meaningful LCNs in
> its console output.  I'm not sure it does but that's how it looked at
> 2am this morning.
>
> Reinstating the backup of the channel & dtv_multiplex tables from a
> backup has produced working channels again but I had to manually update
> the mplexid of tinypop for it to work - and thankfully it does really work.
>
> I hate having to rescan just because Freeview have shuffled channels
> around & I know this causes mythtv a headache so it does its best to
> interpret how to wiggle the changes in without deleting all channels &
> starting again - but this LCN business is just strange.
>
> It's been a long time since I used dvb tools but I'm more than willing
> to provide a dump of a tuned mux to help find out what's going wrong.
>
> Justin

It does all seem rather strange.  I have a feeling that a full reset of 
channel numbers doesn't normally happen unless one 'deletes ALL tuners' 
but maybe your DB poking has worked.  Have you checked your transports 
against eg https://ukfree.tv/transmitters/tv/Pontop_Pike ?

It looks as if TinyPop is in a low power QPSK mux that might not be in 
the linked structure and might have escaped your earlier retunings.  I 
don't usually have trouble with minor Freeview reshuffles, doing the 
'all known transports' procedure, but it did miss the Olympics reshuffle.

I did a laptop full retune after relocation a few days ago and it worked 
as normal, for Sandy Heath.