[mythtvnz] Wellington Channel Retuning 19 June 2012

[Steve V]

>________________________________
> From: tortise <tortise at paradise.net.nz>
>To: stephen at jsw.gen.nz; MythTV in NZ <mythtvnz at lists.linuxnut.co.nz> 
>Sent: Sunday, 17 June 2012 10:13 AM
>Subject: Re: [mythtvnz] Wellington Channel Retuning 19 June 2012
> 
>On 16/06/2012 10:07 p.m., Stephen Worthington wrote:
>> On Sat, 16 Jun 2012 19:07:28 +1200, you wrote:
>>
>>> On Sat, Jun 16, 2012 at 6:47 PM, tortise<tortise at paradise.net.nz>  wrote:
>>>> Wellington users may not be aware of
>>>> http://www.rsm.govt.nz/cms/policy-and-planning/projects/digital-terrestrial-television-frequency-restacking/timing-and-channel-information
>>>>
>>>> For kaukau
>>>>
>>>> 50>  32
>>>> 48>  32
>>>
>>> no 48 goes to 34 I think.
>>>
>>>> 59>  36
>>>>
>>>
>>> Yes I see we are next! (after you I mean).
>>>
>>> Are you suggesting just changing the freqid? I am not sure that will
>>> work if the serviceids change too.
>>>
>>>> I suppose it can also be done through SQL, but for the time it would take to
>>>> do I am presuming one can do this thru
>>>>
>>>> /mythweb/settings/tv/channels
>>>>
>>>> sql seems more risky and would take longer.
>>>>
>>>
>>> No it would be three lines, if simply changing the freqid works (see above)
>>
>> The Kaukau changes are identical to what the Wharite changes in May
>> were, so here is the script I used then:
>>
>> #!/bin/bash
>> # Update the channel frequencies for FreeviewHD from Kaukau for the
>> # 19-Jun-2012 changes.
>> source /etc/mythtv/mysql.txt
>> mysql -u $DBUserName -p$DBPassword -h $DBHostName $DBName<<  EOF
>> drop function if exists calcfreq;
>> delimiter $$
>> create function calcfreq(freqid int) returns int
>> begin
>>      return (506000000+(8000000*(freqid - 25)));
>> end$$
>> delimiter ;
>>
>> set @freqid1 =    50;
>> set @newfreqid1 = 32;
>> set @freqid2 =    48;
>> set @newfreqid2 = 34;
>> set @freqid3 =    59;
>> set @newfreqid3 = 36;
>>
>> update channel set freqid = @newfreqid1 where freqid = @freqid1;
>> update channel set freqid = @newfreqid2 where freqid = @freqid2;
>> update channel set freqid = @newfreqid3 where freqid = @freqid3;
>> update dtv_multiplex set frequency = calcfreq(@newfreqid1) where
>> frequency = calcfreq(@freqid1);
>> update dtv_multiplex set frequency = calcfreq(@newfreqid2) where
>> frequency = calcfreq(@freqid2);
>> update dtv_multiplex set frequency = calcfreq(@newfreqid3) where
>> frequency = calcfreq(@freqid3);
>>
>> drop function calcfreq;
>> EOF
>>
>> exit 0
>>
>>
>> This will change the "freqid" values, and the "frequency" values.  I
>> think the "frequency" value in the dtv_multiplex table is all that
>> matters, but if the "freqid" values are also there in the channel
>> table it would be best to have them matching.  The tuning code for
>> DVB-T looks up the mplexid in the channel table, and uses that to
>> index the dtv_multiplex table for the tuning data.  It uses the
>> "frequency" value from dtv_multiplex to tune to the multiplex, then
>> uses the "serviceid" from the channel table to select the channel on
>> that multiplex.  The "freqid" value in the channel table is used to
>> tune analogue channels, but as far as I can tell it is ignored when
>> tuning digital channels.
>>
>> If you are using one of the other Wellington transmitters affected by
>> this change (Haywards, Fitzherbert or Baxter's Knob) and want to use
>> this script, you will need to fill in the correct values from the URL
>> above in the script's "set" statement pairs.
>>
>> All that is changing are the frequencies the multiplexes are broadcast
>> on - there are no changes to other things like "serviceid" values.
>
>Thanks Stephen, that's really cool and I am sure will be used by more 
>than me!
>
>I note the dev's were talking about removing mysql.txt, I think in favor 
>of xml. I suppose mysql.xml could be used instead but I couldn't code 
>using that in any great hurry. Perhaps its still easy to use?
>
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>
>>> Thanks from me too. I was wondering how I was going to make the channel change.
>
>
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