[mythtv] Ticket #4909: mythbackend does not change input with two mythfrontends watching

[Daniel Kristjansson]

On Fri, 2008-03-14 at 13:13 +0000, David Matthews wrote:
> Bill wrote:
> > I am curious as to why this ticket has been closed.  There is a definite 
> > problem, when the backend is recording, the frontend will only allow 
> > selection of channels on the same transport as the backend is recording.  It 
> > will not automatically select a free DVB card that has the desired channel.
> > 
> > Before multi-rec, mythtv would select the next available card  for the 
> > frontend, when the backend was recording on the first card. With multi-rec, 
> > it seems to attempt the same thing, but instead the next available card, is 
> > the multi-rec virtual card of the first DVB, which then causes the 
> > restriction of channel selection to the same transport.
> > 
> > As a result of this and WAF, I think I'll have to disable the multi-rec (ie 
> > reduce to 1 recording per card). 
> I don't know what the "correct" behaviour should be but it seems 
> unsatisfactory that the behaviour depends on the order in the database. 
>   One possibility would be for Live TV to choose the next free card that 
> is not in use at all and only choose one that is already in use if there 
> is no suitable card.

Allowing browsing across tuners is being addressed on ticket #4501,
unfortunately it's only been in the last 24 hours that a somewhat
efficient way has been created by Shane. I haven't had the time to
review that patch yet, but once we have an efficient browse across
tuners patch this should solve most of the UI problems with locked
multirec recorders as well as implementing this 3 year old feature
request.

BTW "Virtual Card" is really a misnomer. Multirec creates multiple
identical recorders referring to the same device, they are equivalent
except for their cardid order in the DB, which the scheduler uses to 
determine which to use when multiple recorders are equals when it
comes to recording a particular show. Any of these recorders can lock
it's siblings, there is no master recorder, just the recorder which
happens to be the last to release the lock. (Think of two 1 hr
recordings one starting a half hour after the other, the first recorder
used will lock the tuner for the first half hour, then the both will
lock it for another half hour, and then the second recorder will lock
it for the remaining half hour.)

PS There are settings to avoid live tv conflicts, one of which is new
   for multirec, I recommend enabling one or both if you are using
   multirec.

-- Daniel