[mythtv] Padding of recordings

[Michael T. Dean]

On 03/07/2007 08:58 PM, Peter Schachte wrote:
> Martin Long wrote:
>   
>> The problem is, that doesn't provide the required behaviour. If I add
>> padding to the individual recording rules, then it would flag a conflict as
>> opposed to just dropping the padding.
>>
>> The (or at least my) desired behaviour is:
>>
>>    - If a tuner is free, use it to preserve the padding.
>>    - If a tuner isn't free, but not conflicts otherwise, drop the padding. 
>>     
>
> Yes, I'd like something like that, too.  There is the softpad branch, but I
> understand Isaac has said he will not accept it because it violates the
> original purpose of Myth's soft padding.  The problem is you may not want your
> soft padding to be quite that soft.  Do you really want to miss the end of a
> really important program just so you can see a much less important one?
>
> There's a rather large design space here, and a lot to take into account:
>
> 	o The original purpose of the soft padding that's there:  to give 		  slow
> hardware some extra time to get ready to record.  It seems to 		  me, though,
> that that should be a per-tuner configuration, not 		  global.  And I've never
> seen an explanation of what the 			  after-recording soft padding was meant
> for; I can't see why you'd 		  ever need to keep recording after a program ends
> because of slow 		  hardware.)
>
> 	o What channel the program is on.  Some channels are notorious for 		  running
> late, while others keep to schedule pretty well.
>
> 	o The priority of the program.  You might well prefer not to record a 		
> lower priority program than to miss the last few minutes of a high 		  priority
> show that runs late.
>
> 	o The priority of the tuners.  What if you have to choose between 		
> recording two high priority shows on a high priority tuner without 		
> respecting the requested extra recording time and moving one of them 		  to a
> lower priority tuner and respecting the requested extra
> 	  recording time?
>
> 	o The existing start early/end late settings per scheduled program.
>
> 	o The existing automatic program extension for particular program
> 	  genres (intended for sporting programs that often run overtime).
>
> 	o The existing override setting for a particular instance of a
> 	  scheduled item.
>
> So what sounds like a simple idea actually turns out to be pretty complex if
> you want to cater for all needs.

Exactly.  Complex enough that it's unlikely any one person's idea of how 
it should work will always make everyone happy.

>   I think something like this would cover it
> pretty well, without making things too complicated for users:
>
> 	1. A per-tuner start early setting that specifies how long before a
> 	   program starts myth should start tuning the station, but has nothing
> 	   to do with when Myth actually starts *recording*.  This would only
> 	   apply when the tuner is inactive before the recording.
>
> 	2. A per-channel start early and end late setting (kind of like the
> 	   per-channel does-it-run-commercials setting).
>
> 	3. A global Boolean config option specifying whether to drop the
> 	   padding on this program if that's the only way to record it.  Also a
> 	   global Boolean config option specifying whether to drop padding if
> 	   necessary to record on a higher priority tuner (ie, which is more
> 	   important:  a high priority tuner or the padding?).
>
> 	4. No per-program start early and end late settings.  Keep it simple.
>
> 	5. However, there would be a program override setting for start early
> 	   and end late.  The difference is that the per-program settings may
> 	   apply to many showings on different channels, while the override
> 	   settings apply to a specific showing.  This give you full explicit
> 	   control over scheduling if you need it.
>
> 	6. After scheduling the explicit program overrides, the scheduler
> 	   schedules programs from highest priority to lowest,
> 	   allocating tuners from highest priority to lowest, and
> 	   dropping padding on programs if configured to do so and if it's
> 	   necessary to schedule that program.  Also drop padding if configured
> 	   to do so and if doing so allows two equal priority programs both to
> 	   be scheduled on a higher priority tuner.  Never drop padding on a
> 	   higher priority program to make room for a lower priority one.

Or the user could tell Myth what she wants using start early/end late 
(either positive or negative) on the recording rules (including 
recording overrides when appropriate)...

Mike