[mythtv-users] scheduler confusion

[Stephen Worthington]

On Thu, 07 Aug 2014 21:37:00 +0100, you wrote:

>On 07/08/14 19:21, Stephen Worthington wrote:
>> On Thu, 7 Aug 2014 09:58:07 +0100, you wrote:
>>
>>> blind Pete <0123peter at gmail.com> wrote:
>>>
>>>> There are three physical dvb-t tuners on two cards, each is configured
>>>> for five virtual tuners.  15 total.
>>>
>>> First question: Do these all get the same multiplexes, or do different cards get different muxes ? It is VERY important as it has a major effect on how things need to be set up.
>>>
>>>> selectclause: (channel.callsign LIKE 'SBS%' OR channel.callsign = 'NITV') AND cardinput.cardid = 'sbs'
>>> ...
>>>> selectclause: (channel.callsign NOT LIKE ('SBS%') AND channel.callsign <>  'NITV' ) AND  cardinput.cardinputid <> 'sbs'
>>>
>>> AFAIK you should rarely, if ever, have to specify cards/inputs in your recording rules. Normally you simply tell the system *WHAT* you want recording and it works out *WHERE* it can be recorded. If you have multiple tuners that get the same set of channels/muxes then you define these as one source with one set of channels and let the system decide which tuner to use. If the physical tuners get different muxes/channels (eg using different antennae pointing at different transmitters) then you need to define them as separate inputs with different channel lineups - but the system still decides for itself which tuner to use.
>>
>> But, as the devs have told us, the scheduler is not perfect.  It can
>> and does make mistakes in certain situations.  Here in New Zealand up
>> until a few months ago, we had only three multiplexes transmitting.  I
>> have three DVB-T tuners in my box, so there should not have been any
>> way for any programs to not be recorded.  But the scheduler did
>> sometimes manage to assign two different physical tuners to the same
>> multiplex at the same time, despite there being enough multirec tuners
>> that it could have used the same physical tuner.  And then it ran out
>> of physical tuners when I needed to record from all three multiplexes
>> simultaneously.
>>
>> The solution suggested by one of the devs was to use the powerpriority
>> table as the OP is doing.  Here is what I am using:
>>
>[deletia]
>>
>If you have three multiplexes and three tuners, then you don't need to do 
>anything fancy *at all*.
>
>Simply use one tuner for each multiplex. This will involve setting up three 
>sources, each of which only contains the channels available to that multiplex. 
>It is *impossible* for any tuner to use a multiplex it is not assigned to so 
>there can *never* be a clash.
>
>All you need do then is to assign as many tuners to a particular multiplex (they 
>not need have the same number) as the number of programs you need to record 
>simultaneously on that multiplex. Job done!

The downside of using separate sources is that they have to have
separate EPG for each source, so the EPG processing will have to be
done three times and will take much longer.  And, of course, as soon
as another multiplex starts broadcasting, the setup does not work.