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

Stephen Worthington stephen_agent at jsw.gen.nz
Fri May 3 15:50:30 UTC 2013


On Fri, 03 May 2013 09:35:46 -0500, you wrote:

>On Fri, May 03, 2013 at 02:19:52PM +1200, Stephen Worthington wrote:
>> On Thu, 02 May 2013 13:26:44 -0500, you wrote:
>> 
>> >On Fri, May 03, 2013 at 03:01:42AM +1200, Stephen Worthington wrote:
>> >> On Thu, 02 May 2013 09:25:17 -0500, you wrote:
>> >> 
>> >> >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
>> >> 
>> >> OK, that has a lot more detail.  I have put it here:
>> >> 
>> >>   http://www.jsw.gen.nz/mythtv/testsched.txt
>> >
>> >Here's what's happening in a nutshell.  In the initial scheduling
>> >pass, none of the HD showings can be scheduled due to conflicts.  In
>> >the first retry scheduling pass, none of the conflicting programs can
>> >be moved.  In the second retry pass, lower priority showings are tried
>> >and the SD showing at 20:00 is chosen.
>> >
>> >The reason adding an override sometimes works is it essentially limits
>> >the second retry pass to the current showing.  FWIW, there are some
>> >minor changes to this area in master (aka pre-0.27).  They might or
>> >might ot help in this particular case.
>> >
>> >David
>> 
>> But what I do not understand is that there are no conflicts at all for
>> the DVB-T channels.  There are enough DVB-T tuners to record all the
>> programs, so why are there conflicts to resolve?  The scheduler should
>> just be able to assign the available tuners.  The conflicts are only
>> for the S-Video input.
>
>There are conflicts with:
>
>!Bath Crashers                  12 ChoiceT 09 18:30-19:03  1 1 1  C 1 4/1
>!Grand Designs Revisited         3 TV3     09 19:30-20:33  1 5 5  C 5 4/5
>!Great Rift: Africa's Wild -    10 PRIME   09 19:30-20:33  1 10 10  C 10 4/9
>
>David

As I said, I have 3 DVB-T tuners.  There are only 3 DVB-T multiplexes
being transmitted in New Zealand.  So there is no way to get a
conflict on DVB-T except by running out of virtual tuners.  Which
would require recording from 5 channels at once on one of the DVB-T
multiplexes.  The TVNZ multiplex and the Mediaworks multiplex have
only 4 channels transmitted on each.  The Kordia multiplex has more
channels, around 12 I think including the radio ones, but I only ever
record from 3 of them.  So I always have enough DVB-T tuners and
enough virtual tuners on each DVB-T tuner so that there is no conflict
possible.

So where is the conflict coming from?  The source of the non-existent
conflict would seem to be the source of the problem.


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