[mythtv-users] Duplicate detection

[Michael T. Dean]

On 09/19/2016 02:06 PM, Jan Ceuleers wrote:
> On 19/09/16 18:04, Michael T. Dean wrote:
>> Are you using subtitle /and/ description or subtitle /then/
>> description?  If the latter, because the movies have no subtitle, it
>> compares the descriptions, which definitely differ.
> Just subtitle (as I wrote initially). Not subtitle and descriptions, nor
> subtitle then descriptions.
>
> I'm still puzzled.

So I (finally) looked at the code and there's an explicit check for 
subtitle <> '' when using the subtitle dup check method (and similar 
checks for subtitle and description with the subtitle and description 
method, etc.).  In other words, we do not compare empty fields for dup 
detection--we instead treat those as "generic" episodes (meaning 
unidentified episodes), so they're always recorded since we don't know 
which episode it is--just in case you haven't seen it.

So, you could enable dup matching to include the description and it 
should work--except for the fact that you're explicitly trying to ignore 
the descriptions since they differ across your listings sources.  That 
means the only other option to get automated duplicate matching would be 
to include it in your custom rule.  It wouldn't be too terribly 
difficult to do for a "title only" matching mechanism (which you could 
do for a film-only rule)--at least compared to trying to do our full 
dup-matching approaches in a custom rule.  You'd need to add a clause 
that checks that oldrecorded.recstatus (which might also require adding 
oldrecorded as an additional table--but try without, first) is not -3 
(recorded).  Fashioning the proper join and tuning it will likely take 
some experimenting (it would take quite a while for me, so I'm leaving 
it as an exercise for the reader).

Note that there was already a "request" (of sorts) for a new dup 
matching method "title only", and it was closed wontfix ( 
https://code.mythtv.org/trac/ticket/9685 ).  One might be considered if 
someone were to do the patch (though messing with the big, ugly 
scheduler query is not a job for the faint of heart)--but I highly 
recommend getting explicit approval of the idea from David Engel before 
working on it.

Alternatively, you could use a manual approach by simply marking your 
existing rule as inactive and then every couple of weeks (depending on 
how far ahead your listings go) go through your upcoming recordings to 
find any matches and tell it to record those you haven't seen (or, 
better, those you might care to see :) with a separate find one rule.

Mike