[mythtv-users] Ceton vs multirec questions

f-myth-users at media.mit.edu f-myth-users at media.mit.edu
Wed Jul 28 03:26:09 UTC 2021

I'm trying out a Ceton 6ETH on a brand-new v31 backend, into which I've
imported data from a very old backend.  I created all six tuners for
the card and it seems to be working.  But I've noticed something odd
and haven't been successful at finding relevant messages or web pages.
[Searching for mythtv, ceton, and either multirec or reclimit are
finding very little.]

After a few hours of letting it record things, I noticed that MythWeb
suddenly claims I have 10 tuners, and some of the numbers repeat.
(They're not exactly in order, either.)  I wasn't watching it like a
hawk, so I don't know when they appeared, and they're clearly reflected
in the capturecard table as well if I look at it with phpmyadmin or the
like.  (An earlier copy of the Status page, also still in my browser,
only claimed 7 tuners, and I missed it when I glanced at it.  But the
10th tuner affected the alignment of all the text and that's when I
noticed and went back and looked at the earlier page in another tab.)

I'm guessing this is dynamic creation of tuners for multirec.
(I didn't notice any such setting in mythtv-setup, but it appears
that each tuner has reclimit = 2 in the table, which I'm assuming
is the default.)  Since I'm coming from a much, much older version
of Myth, I hadn't seen this in action before.


(a) Can Cetons do multirec?  For some reason I thought they couldn't.

(b) Does this mean (1) a new tuner got created because two different
streams on the same multiplex were being recorded which overlapped in
time, or (2) because -the same channel- was being recorded back to back
(with overlaps, because I have two-minute prerolls and postrolls on
everything), or both (1) and (2)?  [If both work, I'm delighted.]

(c) Should I go back into setup, or the table itself, and raise reclimit
to a much higher value?  If this is record-streams-from-multiplex behavior,
I don't see a reason not to record as many as exist (if that's what the
schedule is calling for), except perhaps (1) load issues on the network
or the backend [which I'll test for], or (2) possibly quadratically-
or exponentially-bad runtime performance of the scheduler (which I have
some vague memory of being discussed in years past but may either not
have existed or may have since been fixed).

[Note that if I do (c), I can also just clear all the tuners and start
fresh if that's easier; I'm sure it's the more-recommended approach,
though mythtv-setup is -so- klunky in setting up these tuners that
short-circuiting it via mysql is extremely tempting.]

(d) I recall discussions about tuner numbering etc.  If I'm right about
the stuff above, and if I raise reclimit a lot, are there any particular
best practices for naming these tuners, or even preemptively creating
database entries for them, to make it more obvious what's going on?
[Since they're all identical, I don't care which might get used first
for LiveTV, so I don't care about that ordering, and I only use LiveTV
about once a quarter or so for minute or two if I'm testing something,
so it's not a priority anyway.]

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