[mythtv-users] how properly to rescan channels

[John Pilkington]

On 11/07/15 16:14, UB40D wrote:
> Executive summary:
>
> how do I do a clean scan for channels, keeping only stuff that works and
> without having to edit lots of channel numbers by hand?
>
> Gory details:
>
> I have a DVB-S2 setup and for the past few weeks I had failures on NHK
> HD recordings where an entry would appear in the recordings but, upon
> clicking on it, the system would say that there was no such video (so I
> then had to delete the entry manually).
>
> Since I was not able to view that channel manually as live TV, I thought
> that perhaps the channel itself had changed (though why would it still
> be on the EIT?) and that it was time for a rescan.
>
> I went into mythtv backend setup.
> Input connections
> DVB: /dev/dvb/adapter0/frontend0 (dvbinput -> EIT)
> scan for channels
>
> using the parameters at
> http://parker1.co.uk/mythtv_freesat.php
> namely
>
> Freq: 10847000
> Polarity: Vertical
> Symbol rate: 23000000
> Mod Sys: DVB-S2
> FEC: 2/3
> Modulation: 8PSK
> Inversion: leave at auto
> Rolloff: leave at 0.35
>
>
>
> and I got to a stage where it said there were a bunch of off-air
> channels (?), with incomprehensible options to delete all, set as
> invisible, ignore all. I did delete all. I had a variety of similarly
> unexplained queries and got stuck when it kept on asking to reassign
> conflicting channels to other channel numbers, manually, for dozens of
> channels. So I gave up, went in the channel editor, did delete all, then
> redid scan for channels.
>
> This appeared to work, but on trying to exit the backend setup I get a
> dialog box (partly unreadable as the end of the message is chopped off)
> that says
>
> Card 1 (type dvbinput) is set to start on channel 3897, which does not
> exist. Card 2 (type dvbinput) is set to start on channel 3897, which do..
>
> and the two options are
> Yes please
> No, I know what I am doing
>
> Yes please WHAT?
> Anyway, clicking Yes please just dismisses the dialog box, leaving me in
> the backend setup.
>
> I have looked around in capture cards, video sources, input connections
> etc and I cannot find where it says that card 1 is set to start on
> channel 3897 or any other channel.

I usually see that it's set to start on channel 'please add' - but I 
think it's inviting you to edit the starting channel in 'input 
connections.'  The 'yes please' simply gives you an opportunity to 
correct something that it sees as a problem, and 'I know what I'm doing' 
is almost always untrue...
>
> What should I do to clean out all channels, rescan what works today and
> be done with it?

I don't have any DVB-S experience, but with DVB-T, 'scan all known 
transports' usually works as an update once I've settled on the ones I 
need - which rarely change and can often be chosen from published lists.
>
> Note also I have 2 tuners and I'd like not to get a bunch of duplicate
> entries for each channel is possible.
>
> Thank you