[mythtv-users] Duplicate matching methods - make program ID an explicit choice

[John Veness]

On 19/05/2016 15:04, Michael T. Dean wrote:
> On 05/19/2016 09:50 AM, Michael T. Dean wrote:
>> It should not be an option as the program ID is the definitive 
>> identifier of a program.  If it's available, it should be used.
>>
>> What you really want is to expand the definition of program ID to 
>> recognize its source dependence.  So, the most straightforward 
>> approach would be to include some source identifier in the program 
>> ID, something like <sourceid>-<programid>.  However, the source 
>> identifier could not be anything like a MythTV Video Source sourceid 
>> because that can change even when the actual source is the same (i.e. 
>> after a Delete all Video Sources).  It could be the Video Source 
>> name, but that would require that the user never change that name 
>> (and know its additional importance). It almost makes sense for it to 
>> be the Video Source xmltvgrabber (for XMLTV or Schedules Direct), 
>> except in some areas the grabber name is changed frequently, though 
>> it ultimately gets its data from the same upstream source.  Ideally, 
>> it would be some value taken from the data provider itself, though I 
>> don't know my XMLTV/SD/EIT data well enough to suggest any particular 
>> value to use for a listings source ID that would be specific to a 
>> given program ID provider.
>>
>> Any patch making this change would need to appropriately update 
>> program, record,  recorded, oldrecorded, and recordedprogram data.
>
> Oh, and then the matching should be done using program ID where both 
> episode have a program ID and the program ID source is the same for 
> both, else it falls back to the user-specified duplicate matching 
> algorithm.
>
> And, really, the duplicate matching itself would be easier with the 
> listings provider ID (program ID source's ID) in a separate column, 
> though the patch would be much more difficult (as it would require 
> modifying program data in the protocol and such).
Thanks Mike. I'm glad you added the paragraph "the matching should be 
done using program ID where both episode have a program ID and the 
program ID source is the same for both, else it falls back to the 
user-specified duplicate matching algorithm" as otherwise, with your 
first response, I didn't see how that would fix the problem when one 
changes listings provider, which at the moment will cause all previous 
episodes to re-record due to all new listings having different format IDs.

It would be great if there was a "universal" program ID that would give 
a particular episode of a particular series the same ID among all 
listings providers, but I don't think this will ever happen.

My problem is particularly with the user interface, where it looks like 
we can control how duplicate matching works (and a few years ago, indeed 
we could) with the subtitle, description, subtitle+description stuff, 
but in most cases we cannot. I don't like UIs that lie to me! At the 
very least, some explanatory text could be added to say that these 
options only take effect when program IDs are missing. Even better if 
there was an advanced tickbox to ignore program IDs when doing duplicate 
matching if we wish to do so.

It has been suggested that one possible fix of the re-record problem 
when changing listing providers is to blank the program ID from all 
oldrecorded entries, which would force duplicate matching to match on 
subtitle etc. I'm happy to do that, even though I dislike throwing away 
information, but others might not be happy with direct database 
manipulation.

Which is why I suggested that, rather than blanking old program IDs, it 
would be better to add an option to ignore old program IDs when 
duplicate matching, which seems a relatively easy fix. If this option 
was added, I'm not sure if that would be best added to individual 
recording rules, which would mean a lot of editing recording rules for 
people but which would give maximum flexibility, or as a global option. 
Personally, I'm slightly preferring the option available in individual 
recording rules because at the moment, even disregarding changing 
listings providers, I have a problem with some series not correctly 
matching duplicates more than others.

John

-- 

John Veness, MythTV user, UK, DVB-T

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