[mythtv-users] EPG Accuracy (Was: record at any time on channel <CHANNEL> is missing in master soon to be .27)

[Michael T. Dean]

On 08/01/2013 02:02 PM, Simon Hobson wrote:
> As an aside, it looks like the program id is<something><series id><episode><series>. Is that a "standard" and Myth derives the series and episode from it (in which case, what happens when there's more than 9 series ro episodes ?), or is the series/episode data held elsewhere (the above pulled from the program table) ?

MythTV doesn't pull any information from parsing the programid.  The 
program ID's sole purpose is to serve as a unique identifier of a 
program for duplicate matching.  If it exists on /both/ the 
previously-recorded program and the current program in the listings, it 
is used as the duplicate check method.  (In your case, one or the other 
showings was likely missing a program ID, or ...)  See 
http://www.mythtv.org/wiki/Duplicate_matching .

In fact, MythTV /can't/ parse the program ID to determine series and 
episode number because MythTV generates the program ID (for any listings 
service that does not provide a program ID--TTBOMK, that means any 
XMLTV-based listings service).  Note, though, that the program ID is 
generated if, and only if, the listings service provides both a season 
(series) and episode number for the showing.  The program ID is 
basically generated from the series ID--which is simply a hash of the 
series title--followed by a one-digit season (series) number in base-36 
(0-Z), followed by episode number in base 10 without leading zeroes.

(Also, the season (series) and episode number in the database are 
neither pulled from the XMLTV data, nor parsed from the program ID 
(that's created from the season (series)/episode number in the XMLTV 
data).  It's pulled from the metadata service (i.e. thetvdb.com), so 
that it matches the metadata service information, regardless of the 
order your provider airs episodes of a series and regardless of whether 
the XMLTV data actually provides season (series) and episode number for 
any given showing.)

Therefore, the question above becomes "What happens when there's more 
than 35 series (seasons)?"  The answer is MythTV will not create a 
program ID for episodes in late seasons (36+), so it will fall back to 
the user-specified duplicate matching technique (i.e. "subtitle + 
description" or "subtitle, then description" or whatever) for any 
episodes in those late seasons.  (Note, also, that it doesn't matter 
when there are more than 9 episodes in a season (series) because MythTV 
will output the entire episode number--whether it's 4 or 14 or 44 or 
149823...)

Note, also, that this program ID generation method was implemented 
around the 0.24 timeframe (IIRC, right after the 0.23 release, so wasn't 
in stable until 0.24).  Before that, there was a flawed encoding used 
for program ID generation.  So, it's also possible that the 
previously-recorded episode was recorded in the 
pre-program-ID-generation-flaw fix days and, therefore, has a broken 
program ID, and the new program with a proper program ID has a different 
program ID, so the episode got recorded, anyway.  If that's the case (if 
both have program IDs and they differ), you'll just have to tell MythTV 
you've already seen any of those episodes you notice in the future that 
will be recorded due to the bad program IDs in your history or just let 
it record them and delete them after.

See: http://www.gossamer-threads.com/lists/mythtv/commits/436907#436907

Mike