[mythtv-users] Input Group Question For Two Dual Tuners

[Stephen Worthington]

On Fri, 1 Jul 2016 05:52:27 +0000 (UTC), you wrote:

>This is probably a very old problem, but google isn't turning up anything useful that's recent.   I have the backend set up to record a few minutes early and a few minutes late for all recordings.   When two shows are scheduled to record back-to-back, the second show doesn't record despite having four Hauppauge tuners (2 dual pci-e tuners) and separate disks dedicated to recording shows. 
>
>I'm hoping that input groups will solve recording two shows back-to-back, but I can't figure them out. 
>
>I tried adding two new input groups and adding a tuner to each. The result was I couldn't watch TV or record and I could not undo the changes in the gui. I recreated the 0.28 backend, so currently there is no cruft from years of in place upgrades and no fancy settings/setup.  Four tuners are minimally configured. 
>Thanks in advance.

Input groups are for tuners that are multi-function, such as DVB-T and
analogue in the same tuner.  Usually, only one of the two functions
can be used at the same time, but the two tuners appear as separate
tuner devices.  So you create an input group and put both tuner
devices in that group and then mythbackend knows to only use one of
the tuners at once.  So it is not at all what you want.

To fix your original problem with back to back recordings needing
overlap, the usually way that is done is to use multirec tuners.  That
is where each physical tuner has multiple virtual tuners assigned to
it, all of which can be recording at once.  This is the normal setup
for DVB-T and DVB-S tuners, where a tuner is capable of tuning to one
frequency at once, but that frequency can broadcast several channels
of data multiplexed together.  So you frequently need to record from
more than one of those channels at once, and it would be very wasteful
to use a physical tuner for each channel.  MythTV supports up to five
multirec tuners per physical tuner.  Multirec tuners are also used to
do the overlap for back to back recordings.  One recording is running
on one multirec tuner, and the new recording for the same channel gets
started on a different multirec tuner.

You did not really give enough information about your setup to be able
to properly diagnose your problem - you did not say what sort of
tuners your Hauppauge units are.  Are they DVB-T/T2, DVB-S/S2, ATSC,
DVB-C, or analogue ones that record from a set top box?  In any case,
if you have four of them, then even if you do not have multirec
configured and they are only capable of recording one channel each, if
you have them all configured for the same source (using the same
sourceid value), then mythbackend should be able to use them to record
overlapping recordings automatically.  So please tell us about how you
have them set up, so we can see what is wrong.