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

[John Pilkington]

On 02/03/2019 23:35, Roger Siddons wrote:
> 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.
 >

Thanks to Roger and Stephen for their thoughts.

EIT has worked fine for me, for years, and still does.  I was hoping to 
find a reason for the recent increase in decoding error-rate, and 
Roger's link is a possible, together with others that I mentioned, and 
the spectrum-clearance program; my BBC mux seems better than itv/Ch4, 
but I tend to steer them to different devices anyway.

I suppose I might have missed some other setting, but my source for 
belief in 'passive scanning' looked fairly robust; it's at the end of 
the thread I quoted earlier...

https://lists.gt.net/mythtv/dev/619014#619014

Cheers,

John P