[mythtv-users] Ceton vs multirec questions

Peter Bennett pb.mythtv at gmail.com
Wed Jul 28 16:15:00 UTC 2021

On 7/28/21 11:34 AM, f-myth-users at media.mit.edu wrote:
> Interesting.  I can find very little about this via a web search:
>    mythtv "schedule as a group"
> returns about three not-very-informative hits.  (Which is surprising,
> since I'd swear I heard about this on the mailing list some time ago,
> and I would have guessed that Google would return those messages.)
> However, all six of the real tuners (the first six rows) in my
> cpturecard table do have "schedgroup" set to 1.  (And all of the
> later entries do not.)
> If this really does override reclimit, then obviously fiddling with
> that won't matter.  But what does schedgroup buy me?  Overlapping
> (same-"channel", from pre/postroll) recordings sharing a tuner?
> (Hope so!)
> The other reason I'm confused re multiplexes etc is that if I go to the
> web interface for the Ceton, I can clearly see that each channel claims
> a whole bunch of "program" entries, and it's a different list for each
> individual channel.  (Some are mostly in the 1-10 range; some have half
> a dozen entries like 1, 10, 2804, etc.)  My assumption was that these
> were different streams multiplexed on the TS stream arriving for that
> channel---if I record the card "by hand" using its web interface and
> just dump the stream into a file using netcat, things like mpv will
> report that there are are huge numbers of audio and video streams:

When using a cable card, the Ceton can only record one channel per 
tuner. If you set Max Recordings to more than one, the pre-roll or 
post-roll for two consecutive recordings on the same channel can be 
accommodated with one tuner, where in previous versions that would use 
two tuners or ignore the pre and post roll if there weer not enough 
tuners. The "schedule as a group" setting, which is now default, allows 
the system to dynamically increase the "Max Recordings" settings when 
the same channel is needed for two recordings at the same time. When Max 
Recordings is more than one, extra (virtual) tuners are created and 
shown in the status.

Multiplexes exist on the wire and the ceton shows them as multiple 
programs per channel, but MythTV cannot take advantage of this to record 
several programs from one channel on one tuner because of the decryption 
done by the cable card, which will only decrypt one program of a channel 
at a time.


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