[mythtv-users] Recordings Fail for one DVB-T multiplex

[John Pilkington]

On 14/06/12 16:00, Mike Perkins wrote:
> On 14/06/12 12:57, John Pilkington wrote:
>> On 14/06/12 11:03, John Pilkington wrote:
>>> On 14/06/12 10:16, David Watkins wrote:
>>>> I'm in the UK on the Crystal Palace transmitter (DVB-T), running 0.25
>>>> fixes.
>>>>
>>>> I've just noticed that ITV4 and Film4 recordings are failing.
>>>>
>>>> Both these channels are on the COM6 multiplex, so probably that whole
>>>> multiplex is failing to tune (I don't have any of the other channels
>>>> on it marked as visible).
>>
>> <snip>
>>>
>>> I would delete that transport and rescan all transports with the 'scan
>>> linked transports' enabled. I have found (but not on Crystal Palace)
>>> that a scan with just the dvb-t2 mux defined will find and populate all
>>> the other muxes; if you start with only SD muxes you may not find HD and
>>> it often takes a few cycles to get the other SD muxes right, but it gets
>>> there in the end.
>>>
>>
>> I must retract this: it used to work, but a test with mythtvsetup
>> today failed
>> to get lock on any channel in 'scan existing transports' modes after
>> manual
>> entry of frequencies. A full scan with an empty transport table found
>> the usual
>> jumble of muxes from various transmitters and it looks as if deleting
>> the ones
>> known to be irrelevant and rescanning 'all known transports' may have
>> worked. I
>> haven't tested recording yet.
>>
>> This is with the current (1 May) ATrpms build of 0.25-fixes on SL6. I
>> did the
>> test in response to an inquiry from dekarl on Ticket #10217. The
>> timings suggest
>> that the 'fix' in #10054 may have caused the change. I don't think I
>> had done
>> any scans in 0.25 before today.
>>
>> It looks as if prior knowledge of mux frequencies is still a great
>> help in
>> sorting out the mess.
>>
> A footnote here: Despite the fact that we are supposed to be completely
> over and done with the digital switchover here (Hannington: North
> Hampshire), yesterday I saw a notice saying that we will have to retune
> yet again within the next month. I didn't notice the date as I was not
> expecting to see such a warning again.
>
> I've no idea why this is necessary and I haven't yet ferreted around to
> find the reason. It's possible the same may be happening with you. I
> *love* having to re-scan.
>

I suspect that the DSO has finished as far as it relates to allocating 
frequencies to specific transmitters, but shuffling the programme 
channels within the muxes is probably done for commercial purposes and I 
would guess it's likely to continue.  If you do have a good set of 
transports defined you can probably just 'scan all known transports' 
without much pain.

My tests today were to test linked scanning starting from a single 
manually entered HD mux frequency.  I used to be able to do that - after 
specifying QAM-256 and writing two IDs to the DB.  Now I can't get lock 
to get it started.