Media Center recording repeat rather than first showing

[IT Troll]

I've encountered something weird with a series recording for a UK sitcom called "Back". For the last two episodes Media Center has changed the scheduled recording so that it records the repeat rather than first showing. This wouldn't be so bad, however the repeat showing is augmented with signing. The repeat is on the same channel but on a different day and time.

I am absolutely positive that it was scheduled to record the first showing, Whilst it does overlap with the recording of another show, I have four tuners and so no conflicts. At some point the schedule is changed to record the repeat. There is absolutely nothing in the logs about a problem or failed recording. The log only records the fact that it recorded the repeat showing.

I checked the guide data for the forthcoming episode and all appears correct (the repeat showing is slightly shorter due to fewer ads). Here are some snippets:

Code: Select all

<Program id="1927" uid="!Program!EP02767120_0009" title="Back" episodeTitle="Back" description="Stephen's on a health kick, Cass embraces student living and Geoff has a dramatic change in his relationship status. &#xD;&#xA;Season 2, Episode 3" shortDescription="Stephen's on a health kick, Cass embraces student living and Geoff has a change in his relationship." language="en-gb" seasonNumber="2" episodeNumber="3" originalAirdate="2021-02-04" keywords="k6,k6002" season="sn340" series="si364" isComedy="true" isSeries="true">
   <ActorRole person="p1904" rank="1" character="Stephen" />
   <ProducerRole person="p5420" rank="1" />
</Program>

<Service id="s11" uid="!Service!EPG123_50716" name="Channel 4 HD" callSign="C4HD" affiliate="!Affiliate!C4" />

<ScheduleEntries service="s11">
   <ScheduleEntry program="1730" startTime="2021-01-29T00:35:00" duration="3000" audioFormat="2" isHdtv="true" isRepeat="true" />
   ...
   <ScheduleEntry program="1927" duration="1800" audioFormat="2" isHdtv="true" isDvs="true" />
   ...
   <ScheduleEntry program="1927" duration="1500" audioFormat="2" isHdtv="true" isDvs="true" isRepeat="true" />

For the coming episode I have changed the scheduled recording to a specified time, to see if that helps.
Has anyone else experienced something like this or know what is going on?

[Space]

There can be many reasons why a particular airing of an episode is not recording. Some of them are listed below (some of them don't pertain to your situation based on the information you provided).

1) None of the tuners you have assigned to this channel are available at the time. Note that just because you have 4 tuners does not mean you have the channel configured to use all of those tuners. Generally all tuners that have access to that channel are assigned to the channel by default, but that may not always be the case.

2) Depending on how your Series is defined, it may not record an episode if that episode has incorrect data. For instance, if your series is set to "HD Preferred" and the airing is missing the isHdtv attribute (due to a guide data error), it will not record that airing if there is another airing that DOES have that attribute.

3) Power outage. If your HTPC is down while the show is airing, it will not be recorded and no error message will be logged regarding that program.

4) Differing program IDs. Sometimes different program IDs are assigned to different versions of a program. If you have your Series defined with a specific program ID, and there are other episodes of that program that are in some way special, and were given a separate program ID, those "specials" will not record. For instance "The Show" and "The Show (enhanced edition)". Sometimes they may even have the same name. Note that I have not really seen this with Gracenote data, but I haven't looked for it either.

5) Airings on different channels. If you set up your Series to record from a specific channel, and the premiere airing of an episode is on a different channel, then that airing will not record. This can happen if a show airs it's episodes on multiple channels.

6) The OAD of the episode is not within 7 days of the airing date if your Series is set to "New". If the OAD date for the episode is incorrect and is set to a date that is more than 7 days in the future or past from the airing date, it will not be considered new, and will not be recorded. So it is possible that an episode that airs on 2/1 but has an OAD of 2/8 will not record due to not being considered "new", however repeats of this episode that air later in the week will record, due to being within 7 days of the 2/8 OAD date.

7) Other reasons I cannot think of right now.

[IT Troll]

Thanks Space, I think I was aware of most of those but most don’t apply in this case. What I find particularly strange is that the correct showings were originally scheduled to record. This rules out many of the potential series matching issues.

1) All tuners are assigned to all channels.

2) I have the HD override flag set on my HD channels and the correct showing was originally scheduled to record.

3) HTPC is on 24/7 and was being watched at the time of the original scheduled recordings.

4) Show IDs match and the correct showings were originally scheduled to record.

5) All showings are on the same channel and the correct showings were originally scheduled to record.

6) The original showing was scheduled so the OAD must have been correct initially. I guess it could have changed at a later point through an EPG update causing the issue. However that does sound like a long shot, especially as it did it twice.

If I had got a signal/tuner error I would understand. It is the silent rescheduling to another showing which has me baffled. The recording schedule must have been changed during a subsequent daily pvrschedule task. The question is why.

[IT Troll]

Another week, another problem "Back" recording. This time the series settings were set to a specific timeslot (20:00) and I watched what happened. I guess the title of the thread should really be Media Center only using one tuner.

The show immediately before this was also being recorded and had a mandatory 5 minutes extra. Media Center did not start the second recording using another tuner (three other tuners sat there doing nothing), but instead waited until the busy tuner was free before starting the recording 5 minutes late. During the whole 5 minutes of waiting, the start time in the schedule was Now.
No tuner errors, recording conflicts or signal warnings given. Not even flagged as a partial recording.

I double checked the tuner sources and all four are mapped correctly and preview correctly. With OTA Media Center can build up a list of discovered garbage frequencies, but only the four shown are enabled.

My only thought is to perhaps re-sort the sources so that the active ones are at the top of this list. This is a real pain to do in the Meda Center UI. Are there any utilities which can edit the channel sources in a less painful way? Does the old Guide Tool do this?

[IT Troll]

Neither the old Guide Tool or EPG123 allow you to edit the sources. So I re-ordered them in the UI. Let's see if that makes any difference...

[dmagerl]

I've noticed that once WMC gets it in its head to record at a certain time and channel, it sticks with it, nothing you can do.

When I tell WMC to record from a specific channel, and one day the signal strength on that channel is a bit poor, it will go off and try to record from a different channel/different time. Once it does that, it sticks with that channel and time. So I'd say that one day, for some reason your primary recording failed and it switched to an alternate channel/time and now its stuck on that alternate channel/time.

The only way to fix it is to delete the series recording and then add it back with the desired channel/time. Usually that fixes it for me but not always. I'm battling an issue right now where WMC decided to switch the channel it records "This Old House" from an HD channel to an SD channel even though its set to record only from the channel I specified. WMC just ignores all the series preferences and does it's own thing. Deleting the series and re-adding hasnt fixed it yet. It's worked fine for years. Why it decided to switch is unknown.

[IT Troll]

So I'd say that one day, for some reason your primary recording failed and it switched to an alternate channel/time and now its stuck on that alternate channel/time.

The only way to fix it is to delete the series recording and then add it back with the desired channel/time.

It didn't switch channel and for this latest recording it didn't switch time; just waited and started the recording 5 minutes late.
I will delete and re-add the series recording though to rule that out. Thanks.

[garyan2]

I'll have to look at the code again and find it, but WMC considers a recording a success if it starts up to 5 minutes late (from the schedule entry start time, not including padding) and a percentage of the program length is recorded (could end early) IIRC. It takes these minimum requirements into account when determining which schedule entries to record. Basically, WMC decided it is best to only use 1 tuner to fulfill both recordings.

[Space]

In my experience, if a program to be recorded ends within 5 minutes of the start of another program to record (on the same channel or not), it will schedule both of those airings to record, even if there is only one tuner available. For instance, if program1 ends at 10:05pm and program2 starts at 10:00pm, it will schedule both those airings to record, even though they overlap (by 5 minutes or less).

If at the time program2 is scheduled to record, there is another tuner available, it will start that program recording on the other tuner at the correct time (10:00pm). Otherwise, it will wait until program1 is over, see that it is about to start recording program2 late and then try to reschedule it to record a future airing.

However, if there is no other tuner available and no other airing of that program in the guide that it can record, then it will start recording program2 after program1 ends at 10:05pm, causing the first 5 minutes of program2 to be missed. There is no notification in WMC that this will happen or has happened and it is a bit annoying. I have gotten around this by adding a 10 minute hard tail padding to program1, but it is not an ideal solution. Fortunately this is a rare circumstance if you have multiple tuners.

Note that this was done on purpose and is a feature called "enhanced conflict resolution" and was introduced in the Vista version of WMC. It was primarily meant for people with only one tuner that would complain about one of the programs not recording due to a small overlap. I don't know if there is a way to turn this feature off, but if there were I would definitely do so as I would rather see a conflict indication (so that I could manually resolve it) rather than have it silently record a partial program.

[IT Troll]

If at the time program2 is scheduled to record, there is another tuner available, it will start that program recording on the other tuner at the correct time (10:00pm). Otherwise, it will wait until program1 is over, see that it is about to start recording program2 late and then try to reschedule it to record a future airing.

Yes, this is what I would expect to happen and I am sure this normally happens. It you have the mandatory time pad and you have an available tuner it should use two tuners to record the overlap.

If you use the optional (when possible) time pad then it will only use one tuner and not record the overlap.

For this particular recording Media Center seems to be behaving as if I only have one tuner, rather than four. Meaning it will either try to reschedule the recording because it is late starting, or just wait until until the “one” tuner is free. Perhaps the ‘enhanced conflict resolution’ is getting confused (nice article, thanks). I think I will give the preceding series recording a mandatory 10 minute time pad. Hopefully that will force it to schedule another tuner.

[CyberSimian]

I think I will give the preceding series recording a mandatory 10 minute time pad. Hopefully that will force it to schedule another tuner.

Isn't this "old news"? I was doing this back in 2009.

I had 8 tuners in my HTPC, and in order to force WMC to use separate tuners for consecutive programmes (whether on the same channel or on different channels) I had manually to edit every recording that I scheduled, and increase the padding to 10 minutes. Quite annoying, really.

This was one of the reasons that after five years I moved from WMC to MediaPortal. MediaPortal honours the specified padding, and (even better) can record multiple channels concurrently using only one tuner (if those channels are on the same MUX). So, for example, I could record BBC1 HD, BBC2 HD, ITV1 HD, Four HD, and Five HD concurrently, and still use only one tuner. The third reason for leaving WMC was the increasingly erratic (and final demise) of the Microsoft EPG. I now use the EPG that is broadcast with the TV signals. WMC could also use that EPG, but not for the HD channels in the UK. MediaPortal can use the broadcast EPG for all channels in the UK (both SD and HD).

Apologies if this sounds like a plug for MediaPortal. MP is not without its deficiencies, but compared to WMC, MP provides more of what I want, and less of what I don't want.

-- from CyberSimian in the UK

[IT Troll]

Isn't this "old news"? I was doing this back in 2009.

Thanks for confirming. I think we have discussed aspects of this before. I was aware of the differences in behaviour between mandatory and optional (when possible) time pads. However, despite years of usage I hadn't picked up on this strange reschedule/wait behaviour for consecutive programs when the mandatory time pad is set to 5 minutes.

I guess it kind of makes sense if you only have one or two tuners. Media Center is trying to make the most efficient use of the tuners to maximise recording capacity whilst avoiding conflicts. The behaviour is somewhat unwanted though when you have tuners sat their doing nothing. It wouldn't be so bad if you could set this as a recording default, however only the optional periods are configurable. I wonder if this can be modded...

[Space]

Most things about WMC is "old news", but some of it has been lost with time.

The 10-minute hard padding is a fairly well-known method of forcing two back-to-back recordings on the same channel to record on separate tuners so that post padding is maintained on both airings without cutting off the beginning of the second airing. However, I don't think it is as well known that even if you are not using padding, and the shows are on different channels, you can still end up with a recording missing the first x minutes (up to 5 minutes). There are probably many people that ended up with a recording missing the first 5 minutes and not knowing why.

This issue with back-to-back recordings on the same channel is the most common complaint regarding the "10 minute hard padding" fix, so that is the main one people know about. Usually it's people who add a 5-minute hard padding to a Series and there are two episodes of that series that are airing back to back, and the padding on the first show causes it to add 5 minutes to the end of the first recording while cutting off that 5 minutes at the start of the second one.

As as far as these things being the same, I am not sure they are. Like I mentioned, I've seen WMC reschedule the second recording (if it can) if it is starting late. I do not see that attempted rescheduling with back-to-back recordings on the same channel from the same Series. Although testing would be required to be sure of this, as it's been a while since I've encountered it.

[IT Troll]

Tonight’s show recorded fine, with the 10 minute mandatory time pad forcing the use of two tuners to record the consecutive shows with an overlap.

I think what foxed me initially was how Media Center would happily schedule the recordings with the 5 minute mandatory overlap. But then, at the last moment, would reschedule the second recording to another showing without logging any event. To do that for 5 minutes, but not 10 minutes, makes no sense and must be a logic bug.

Anyway, at least I know how to work around it.

[Space]

Interesting. This would seem to indicate that it does not record the program on another tuner, if available, on-the-fly, and instead just reschedules to another airing on-the-fly. My memory is foggy, but I'm pretty sure I've seen it use another tuner in this circumstance, but I may be wrong.

Also, the 10 minute hard padding was explicitly designed to do that. It forces a program collision so that one of the programs needs to be scheduled to record on another tuner or at another airing time. Unfortunately, a side-affect of this is that it also adds 10-minutes of padding to the recording (which you may not want).

[IT Troll]

The 10 minute hard padding is indeed working as expected. Logically, it should work exactly the same with 5 minutes hard padding.

However, it would seem that ‘enhanced conflict resolution’ is kicking in even when there is no conflict (plenty of free tuners). It’s first strategy is to change to a different showing if possible. Failing that, it will miss the first 5 minutes from the second recording.

To be clear, I have only experienced this in cases of consecutive series recordings on the same channel. The description of ECR implies that it is designed to resolve conflicts occurring on different channels. So it really shouldn’t be stepping in and messing with the schedule.

[Space]

Ah, yes, I missed that. I do think it works differently when the two shows are on the same channel and the overlap is caused by padding. I wasn't sure if it had to be the same Series or if it could also be two separate Series. It may even work differently if the overlap is caused by user padding (and not that they overlap due to the schedule) even on different channels. I haven't really done any testing or payed attention closely.

[CyberSimian]

The 10 minute hard padding is indeed working as expected. Logically, it should work exactly the same with 5 minutes hard padding.

And it does... in Vista WMC (which I used for five years).

For some reason, Microsoft changed this area of WMC in Windows 7 so that it was necessary to specify 10 minutes of explicit padding (not default padding), whereas in Vista WMC, 5 minutes of explicit padding was enough to force the use of separate tuners. Possibly this was part of the rescheduling logic. I had so many tuners that I never encountered rescheduling, so I don't know whether Vista WMC actually supported rescheduling (perhaps the rescheduling logic was introduced or enhanced for Windows 7).

-- from CyberSimian in the UK

[Space]

I believe that it's not that it "was enough", it was specifically 5-minutes of hard padding that disabled the 'enhanced conflict resolution', if you used anything else, like 10 minutes of hard padding, it would not disable it. They just changed which option disabled it from explicit 5-minutes hard padding to explicit 10-minutes hard padding in later versions of WMC for some reason.