[mythtv-users] 3 Mux but recording schedule indicating using 4 tuners?

Michael T. Dean mtdean at thirdcontact.com
Sun Sep 18 22:51:31 UTC 2011

On 09/18/2011 05:38 PM, Ronald Frazier wrote:
> On Sun, Sep 18, 2011 at 5:00 PM, Michael T. Dean wrote:
>> Delete all capture cards, then create the capture cards in the reverse
>> order you want them used for Live TV and re-connect inputs in the order
>> you want them used for recordings.  Note that the 2 can be different
>> orders...
> You know, you said this yesterday, but I didn't quite catch the subtle
> distinction there. Live TV is based on the (reverse) order the cards
> are created,

Technically, this is only true when you enable, "Avoid conflicts between 
Live TV and scheduled shows," but I got too lazy to actually type that 
part, again.  :)  If you don't enable "Avoid conflicts between Live TV 
and scheduled shows," Live TV will choose the default input of the 
"most-preferred" card on the /local/ backend, and if there are no 
available cards on the local backend, it will choose the most-preferred card

>   and recordings are based on the order of the input
> linking? I didn't know that...I thought both were based on the input
> order. So here is a question...if LiveTv goes by the card order, then
> what order does it use when there are multiple inputs for a card?

It always chooses the "Default" input of the most-preferred card (the 
one you specify in mythtv-setup).  I'm 99.99999% positive this means 
that Live TV will "skip" additional inputs on a given card to grab the 
next card if you happen to have a card with multiple inputs where the 
default input is in use at the time you start Live TV, but the other 
inputs are available.

>   Does
> it choose the last card, and then the last input for that card, or is
> it the last card, and then the first input for that card?
> Furthermore, I'm confused about another thing. There has been this
> advice about creating your virtual tuners, and then at the end going
> back and adding 1 more virtual tuner per recorder. This was to avoid 2
> livetv sessions from grabbing virtual tuners on the same card.
> However, that seems to imply that livetv tuner is chosen by the order
> of the inputs. So I really don't see how the card order comes into
> play. Can you elaborate on this a bit? If it makes it easier to
> explain, you can even write it in pseudo code if you want.

In truth, the key point here is that multirec was implemented 
differently from how MythTV was implemented before multirec.  It turns 
out that when multirec was added, instead of using the, er, 
"traditional" approach of having a single card with multiple inputs 
(i.e. creating only virtual inputs), it was developed using multiple 
virtual cards each having one input.  Therefore, when you add virtual 
tuners, you're actually adding a new card /and/ a new input.

In truth, I have a feeling I know where your brain is trying to go with 
this (even if, maybe, it hasn't quite gotten there)...

MMlosh on IRC asked a question just the other day, which got me thinking 
about it.  See 
http://irc.mythtv.org/ircLog/channel/1/2011-09-15:16:22:56 and read 
through, especially, the two comments at 16:32.  I'd be interested in 
seeing a patch (though it may take some convincing to get those who 
spent a ton of time testing the current implementation to consider 
allowing such a major change).


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