[mythtv-users] DVB-T bug when recording multiple programs on the same multiplex?

[William Uther]

> Message: 5
> Date: Tue, 26 Oct 2010 22:22:27 +0100
> From: John Pilkington <J.Pilk at tesco.net>
> Subject: Re: [mythtv-users] DVB-T bug when recording multiple programs
> 	on the same multiplex?
> 
> I suggest that in 'Schedule Options' you try changing 'Use any available 
> input' to 'Prefer Input 3' or 'Prefer Input 4' etc as you would like it 
> to be, and see what happens.  If it works like that you may be happy. 
> Otherwise I suggest deleting all your tuners and setting them up again - 
> or seeing if you get any other suggestions :-)

Ahh - interesting thought.  It might solve this problem, but it still feels like it is fixing this one instance of the problem by tweaking.  When the scheduler makes another instance of the problem and I don't catch it, then I'll just have the same issue.

Interestingly I saw an example tonight of where the multiple recordings on the one multiplex worked.

There were back to back episodes of The Big Bang Theory on one channel.  I have The Big Bang Theory set up to record 15 minutes long.  (Normally I use pre-roll and post-roll for this, but with some shows I've set it explicitly.  The pre-roll and post roll will be dropped if a multiplex is already tuned and hence the lineup I described in my previous email fits on two tuners.)

With the episodes recording long, I get one episode on one cardid and the second episode on the other cardid for the same adaptor.  That setup works fine.

So the problem is when Myth tries to start recording a second channel, but if it wants to 'just' record a second program on the same channel then it works.

> Message: 17
> Date: Tue, 26 Oct 2010 23:38:48 +0100
> From: John Pilkington <J.Pilk at tesco.net>
> Subject: Re: [mythtv-users] DVB-T bug when recording multiple programs
> 	on the	same multiplex?

> On 26/10/10 12:47, William Uther wrote:
>> Hi,
>>   I have a weird issue that I wanted to ask about before possibly filing a bug report.  I have two DVB-T tuners.  Each is set up to record up to two programs if they're on the same multiplex.  This gives me four virtual tuners, 1 and 2 are on adaptor0 and 3 and 4 are on adaptor1.
>> 
>> My standard evening lineup is:
>> 
>>   7:00-7:30pm ABC News (that's Australian ABC, not US ABC :) on ABC1
>>   7:15-7:35pm Daily Show on ABC2
>>   7:30-8:00pm The 7:30 Report on ABC1
>>   7:35-8:00pm Colbert Report on ABC2
>> 
>> ABC1 and ABC2 are on the same multiplex.  This is normally scheduled with the ABC1 shows being recorded by tuner 1 and the ABC2 shows by tuner 2.  i.e. all four shows are actually being recorded on the same DVB-T tuner.
>> 
>> When this lineup is scheduled, what ends up being recorded is:
>> 
>>   7:00-7:15pm ABC News on ABC1
>>   7:15-7:30pm Daily Show on ABC2
>>   7:30-7:35pm The 7:30 Report on ABC1
>>   7:35-8:00pm Colbert Report on ABC2
>> 
>> i.e. if there is a recording already happening through one virtual tuner when the second virtual tuner for the same card wants to start recording a new show on that same multiplex, then the recording on the first tuner is stopped prematurely.
>> 
>> Does anyone else see this behaviour?
>> 
>> What can I do to help debug?
>> 
>> Cheers,
>> 
>> Will       :-}
>> 
> 
> Let me come back on this again.  I don't think I have tried the 
> scheduler on a programme mix quite like this, but does your system 
> normally start and stop recording at the listed change times with no 
> overlap allowed?

As mentioned above, I normally use pre-roll and post-roll for catching show time variance.  This will automatically be dropped if there is a shortage of tuners, or if a tuner will already be tuned to a particular multiplex.

> I have front and back margins, so that around 
> changeover one channel needs two (virtual) tuners.  Between 7:30 and 
> 7:35 I would expect all four of your available cardids to be active, not 
> just the two that you seem to get.  Another 'Schedule Option' to try?

Again, if I wanted to just fix this instance of the problem, then yes, this would probably work (and I think I'll make this tweak just to check it fixes this instance of the problem).  But I want to track down the bug, not avoid it. :)  (and I've just made the change - it seems to adjust the schedule in the way you'd expect, which would appear to work around the problem.  Again - I want to fix it, not work around it. :)

Cheers,

Will        :-}