[mythtv-users] scheduler confusion

[Mike Perkins]

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!

-- 

Mike Perkins