[mythtv-users] Active EIT data collection gives some defective recordings; passive scanning not working.

[Roger Siddons]

On Sun, 03 Mar 2019 05:04:41 +1300
Stephen Worthington <stephen_agent at jsw.gen.nz> wrote:

> On Sat, 2 Mar 2019 14:09:19 +0000, you wrote:
> 
> >Recently the number of defects rose again.  

Most likely the recent weather
https://www.a516digital.com/2019/02/as-weather-disrupts-tv-reception.html

> >I tried disabling active scanning on *all* tuners.  I had understood 
> >that passive scanning would continue to collect EIT data, for all
> >muxes, as long as some recordings were being made 

I thought passive scanning only updates the mux (possibly
channel) of the recording. I'd expect to see 7 days for your popular
channels/muxes and eventually 0 for infrequent ones.

EIT might be cross-channel but that doesn't mean Myth uses it.
Otherwise why does the active scanner cycle through all channels ?

> > They seemed less frequent when I stopped active 
> > EIT scanning with the USB tuners, using only the PCI card.

Good move. I believe the option actually starts a new scanner on the
tuner rather than allowing the *solitary* scanner to use the tuner.
(Years ago there were issues with multiple scanners
conflicting/interfering, particularly on lower-quality dual USB tuners).

There's no reason to ever run more than 1 scanner on a video
source. "New" EIT data is frequent and the scheduler gets repeatedly
re-run pointlessly, which won't help your loads.

> In
> theory, it would be possible to get a tuner that is recording to also
> receive the EIT data at the same time, but I do not think MythTV does
> that.  

It does. 
http://lists.mythtv.org/pipermail/mythtv-users/2012-March/330012.html 

> However, I thought that use of a tuner for EIT reception gave
> way automatically when the tuner was needed for a recording, and
> started again automatically afterwards.
> 

Active scanning will stop and give up its tuner for recording or
shutdown.