[mythtv-users] Companion to "Max episodes" setting...

[Peter Schachte]

On Sun, Jul 23, 2006 at 11:38:26AM -0700, chris at cpr.homelinux.net wrote:
> One of the problems I have with the current system of recording 
> priorities and auto-expire methods is that it's fairly rigid in the 
> way it ranks shows.  People's opinion of the relative value of 
> recordings is a little more variable.
> 
> The solution to that problem would be to have a "min episodes" 
> setting for each rule as well.  That would tell the auto-expire 
> routine "when there are only X episodes of this show left, they are 
> no longer elegible for auto-expire".

But this has the same rigidity problem.  If some really important
movies fill your disk and your supply of south park and simpsons drops
too low, then what?  You probably would want to lose your last few
episodes of these low priority shows to make room for a high priority
recording.

I think the problem you're addressing is the "law of diminishing
returns" from economics.  Having an episode of south park on your disk
has some value, but the second episode is less valuable, and the tenth
is much less valuable.

So rather than a "min episodes" setting for each program, how about a
"diminishing priority" setting?  With this, the priority of a
recording would be the configured priority minus the diminishing
priority setting times the number of younger recordings of that show.
So if south park has a priority of 3 and a diminishing priority
setting of 2, then the youngest south park episode is priority 3, the
second youngest is priority 1, the third is -1, and so on.  Then
supposing you have simpsons at priority 4 with a diminishing priority
of 1, and family guy at priority 2 with diminishing priority of 0, and
assume you have 3 copies of each, then when autoexpire kicks in, myth
would delete them in this order:

	Effective Priority	Show
		-1		South Park
		 1		South Park
		 2		Simpsons
		 2		Family Guy
		 2		Family Guy
		 2		Family Guy
		 3		Simpsons
		 3		South Park
		 4		Simpsons

In fact, with this setting available, I'd probably not usually bother
with max_episodes at all, I'd just assign most series a diminishing
priority setting of 2 or 3.  This would keep old shows as long as
space is available, and then start deleting the oldest episodes of
shows with higher priority to leave room for the newest episodes of
shows with lower priority.

-- 
Peter Schachte              A LISP programmer knows the value of everything,
schachte at cs.mu.OZ.AU        but the cost of nothing.
www.cs.mu.oz.au/~schachte/      -- Alan Perlis 
Phone: +61 3 8344 1338