[mythtv-users] Scheduler seems to think I am recording too many programs at once

[David Engel]

On Fri, May 03, 2013 at 12:04:03AM +1200, Stephen Worthington wrote:
> On Thu, 02 May 2013 07:18:50 -0400, you wrote:
> 
> >On 05/02/2013 12:56 AM, Stephen Worthington wrote:
> >> I was just checking the scheduling for the new EPG received today, and
> >> I found that one program "Seven Sharp" was not recording at its usual
> >> time of 19:00 on TV ONE, but instead was recording at 20:00 from the
> >> TVONE PLUS1 channel which retransmits TV ONE an hour later, but in SD
> >> instead of HD.  I have occasionally seen this sort of thing happen
> >> before, always when I am recording lots of programs at the same time.
> >> It has always seemed to me that the scheduler must have some limit for
> >> the number of programs it will record at one time and when it goes
> >> over that limit, it tries to reschedule one or more of them.  If I add
> >> an override to force "Seven Sharp" to record from TV ONE at 19:00, the
> >> scheduler is happy to do that and does not seem to make any other
> >> changes.
> >>
> >> Here is the schedule for that time period, without the override:
> >> [Time]       [Callsign]-[Program name]
> >> 17:30:18:30  DISCO - Mythbusters
> >> 18:00-19:03  TV ONE - One News At 6pm
> >> 18:00-19:03  TV3 - 3 News
> >> 18:30-19:03  ChoiceTV - Bath Crashers
> >> 19:00-19:33  TV ONE - Seven Sharp  (yellow, "Find Daily -3 Later
> >> Showing")
> >> 19:00-19:33  TV ONE-S - Seven Sharp (yellow, "Find Daily -7 Later
> >> Showing")
> >> 19:00-19:33  TV3 - Campbell Live
> >> 19:30-19:33  TV2 - Police Ten 7
> >> 19:30-20:30  HISCH - Mysteries At The Museum (yellow, "Channel Record
> >> +0 Later Showing")
> >> 19:30-20:30  KNOWLGE - Who Do You Think You Are? Aus
> >> 19:30-20:33  PRIME - Great Rift: Africas Wild
> >> 19:30-20:33  TV3 - Grand Designs Revisited
> >> 20:00-20:30  CRIME&  - Traffic Blues (yellow "Channel Record +0 Later
> >> Showing")
> >> 20:00-20:33  TV2 - RBT
> >> 20:00-20:33  TVONE PLUS1 - Seven Sharp
> >> 20:29-21:33  TV3 - Bones
> >>
> >> In the above, TV ONE, TV2 and TVONE PLUS1 are transmitted on the same
> >> DVB-T multiplex, PRIME and ChoiceTV are on the same DVB-T mux, and TV3
> >> is on the third DVB-T mux.  TV ONE-S is an SD version of TV ONE on a
> >> DVB-S mux.  The other channels are all on Sky TV which is recorded
> >> from a set top box via one S-Video card (so there is only one tuner
> >> for those channels).  The three DVB-T muxes are on one source, the
> >> DVB-S muxes on another source, and Sky TV is on the third source.  All
> >> the DVB-T and DVB-S tuners are set up with 4 multirec virtual tuners
> >> each, and I have 3 DVB-T tuners and 2 DVB-S ones.  Since I have as
> >> many DVB-T tuners as there are DVB-T muxes being transmitted, I should
> >> never have to use the TVONE PLUS1 channel at all as I should always
> >> have enough tuners to record everything I need on the first showing.
> >>
> >> So, does anyone know if there is some sort of limit in the scheduler
> >> on the number of programs that will record at any one time?  And if
> >> so, what it is and how it works?  Is there a setting I can adjust for
> >> it?
> >
> >No limit.  The only limit is the number of tuners (physical and virtual) 
> >you have.  MythTV will gladly work your system so hard that the hardware 
> >fails to keep up and everything fails miserably if you tell it to.
> >
> >> I have 5 recording drives, so whatever is causing this sort of
> >> rescheduling is not taking that into account, as I can easily record
> >> at least 10 programs simultaneously, and probably more, as long as the
> >> recordings use all the drives (and they normally do).
> >
> >It is almost definitely a priority modifier on the other showing causing 
> >it to be preferred.  This could be channel or input or HDTV or any of a 
> >number of other priority modifiers.  You can see what's happening by 
> >running:
> >
> >mythbackend -v schedule --loglevel debug --printsched
> >
> >before the shows air and without the override in place.
> >
> >> Also, is there a way to mark the TVONE PLUS1 channel as SD and the TV
> >> ONE channel as HD and tell the scheduler to always record the HD
> >> programming unless there is an actual clash?
> >
> >No, there's no such thing as an "HD" channel--only channels that have 
> >programs which may or may not be HDTV.  So, it's up to your guide data 
> >to properly mark programs as HDTV or not.
> >
> >You can set priority modifiers on channels (and starting with 0.27, 
> >they'll work the way you think they would work), but then again, 
> >priority modifiers you've already set are probably what's causing MythTV 
> >to record shows in such a way that you think the scheduler is wrong...  ;)
> >
> >Mike
> 
> The --printsched option looks like it is really useful.  I have put
> the result on my web server here:
> 
>   http://www.jsw.gen.nz/mythtv/sched.txt
> 
> If I paste it into a post, its gets word wrapped and unreadable.  For
> readability I also cut down the output to just the bit between times
> where there is nothing recording, so in theory nothing before or after
> the bit posted would affect the scheduling at the problem time.
> 
> If, as I am assuming, the P=Priority column is the fully calculated
> priority value for the scheduled recording, the I do not understand
> what is going on.  The "Seven Sharp" scheduled to actually record from
> TVONE PLUS1 has a priority of -4, but the one that is not going to
> record from TV ONE has a priority of -3.
> 
> The channel priorities are: TV ONE is 0, TVONE PLUS1 is -1, which
> explains the difference between the two recording priorities.  But it
> is still going to record the wrong one.

I'm pretty sure Mike meant that to be --testsched and not
--printsched.  And don't snip any of the output.  It's the cryptic
details that explains what is going on and why.

David
-- 
David Engel
david at istwok.net