[mythtv-users] the right way to do tuner priority?

[Michael T. Dean]

On 09/29/2014 09:44 AM, Brian J. Murrell wrote:
> I know there has been much controversy in the past about how to properly
> assign tuner priorities and that historically, the only proper way to
> influence tuner scheduling choice was simply to add the tuners in the
> order that you want MythTV to use them.  Additionally to that, I recall
> that there was a way that many people were trying to set tuner
> priorities but the reality is that it was not doing what they thought it
> was doing.

The proper way to set tuner "priority" is to set Order and not set 
Priority.  Input Priority is something that can be set only in a 
recording rule and generally won't do what you expect.  Instead, you 
should set Schedule Order and Live TV Order in mythtv-setup for all of 
your capture devices, and MythTV will use them in the order specified.

> But I also recall some discussion recently about how tuner priority was
> fixed so that one could actually set priorities on tuners and it would
> have the expected/desired effect.  I don't recall the details however.

Channel Priority has been changed to work like people expected it to 
work (this isn't a fix because nothing was broken, before, except 
people's understanding of how it worked).

There is work being done in master to encourage the scheduler to choose 
an already-in-use capture device that's tuned to the needed multiplex 
for new recordings, even if that's a device whose Schedule Order is 
later.  This means that MythTV will start more recordings with 
multirec--but may still miss just as many (or more or less for some 
people in some situations) recordings, since conflicts depend on what 
all else you're recording when a new recording is supposed to start, 
what all else you're supposed to start recording at the same time as the 
new recording as well as during the recording (and all those recordings 
will affect conflicts for shows scheduled to record during their 
broadcasts and ...).  This, too, is not a fix (because it's not 
currently broken).

> What I am trying to fix is that in a given (2h1m) timeslot this evening,
> I have a recording occurring on a digital (clearqam) tuner on a given
> sub-channel on a given multiplex (channel "102", subchannel "936") and
> then 30 minutes into that recording, there is another show on the same
> digtial channel, different subchannel that I want to record.  But rather
> than using that same digital tuner, the scheduler is scheduling it to
> record on a completely different, analog tuner.

If this is a one-time issue, the right solution is a one-time override 
rule ("Record this showing" or "Don't record" the showing you don't want 
it to record or whatever).

If, however, it's a persistent issue (occurring most weeks) and if you 
have properly specified your Schedule Order, then the simplest solution 
is the generally right solution:  just adjust the recording rule 
priority of the rules for the shows that record at/around the same time 
as the show that's being bumped so that the shows are placed on inputs 
appropriately to give you the desired outcome.

> I.e.:
>
> 2014-09-29 00:00:03.853011 I  Dancing With the Stars         102-936 WWTI  29 20:00-22:01  2  1  1  A  1 0
> 2014-09-29 00:00:03.853247 I  Mom - Hepatitis and Lemon Zest       7 WWNY  29 20:31-21:00  1 12 12  A 12 0/-3
>
> Where "WWNY" also exists on 102-77.
>
> In fact, there are other less-than-satisfactory scheduling decisions
> being made in that same time-slot:
>
> 2014-09-29 00:00:03.853554 I  Scorpion - Single Point of Failure 100-7 CITY  29 21:00-21:59  2  8  8  A  8 0
>
> is also being shown on WWNY at 21:01-21:59 (so starting a minute later
> than the above scheduled recording).
>
> Ahhh.  But one thing worth noting is that WWNY, on both analog and
> digital have a channel priority of -10, where every other channel's
> priority is at 0.  The reason for the -10 is that that is CBS and they
> are horrible at keeping to their schedule on Sunday evenings.

So, as you've noticed, you've told it to preferentially record shows on 
other channels, so it's doing what you ask.

> TBH, I really only want them de-prioritized on Sunday evenings and not
> really all of the time, but MythTV can't handle that.

Yes it can.

>    Not without some
> external database fiddling at least.

None required (or recommended).  You can use Custom Priorities.

Mike