[mythtv-users] USA OTA FCC frequency rescan?

Klaas de Waal klaas.de.waal at gmail.com
Tue Aug 13 15:35:12 UTC 2019

On Tue, 13 Aug 2019 at 16:05, James Abernathy <jfabernathy at gmail.com> wrote:
> On 8/13/19 9:53 AM, Jay Harbeston wrote:
> >
> >> On Aug 13, 2019, at 9:12 AM, James Abernathy <jfabernathy at gmail.com> wrote:
> >>
> >>
> >>> On Aug 13, 2019, at 8:18 AM, Justin Alcorn <justin at jalcorn.net> wrote:
> >>>
> >>> Once you create the file with the sql statements, do:
> >>>
> >>> mysql -u [mythtvusername] -p mythconverg < [sqlcommandsfilename]
> >>>
> >>> it'll prompt for the database password
> >>> --
> >>> Justin B. Alcorn
> >>> The views expressed are not necessarily my own, much less anyone else's
> >>> PGP Fingerprint CCEB F776 C3FD 1050 C8DB  532E B8B9 BED7 7764 406C
> >>>
> >> Thanks,
> >>
> >> I will be out of town on the day the rescan is needed.  So this all looks simple enough to do via ssh thru my home VPN remotely.  If it works great, but if it doesn’t then I don’t get some recordings.  No difference if I just ignored the rescan till I got home.
> >>
> >> It’s worth a shot anyway.
> >>
> > Note that you will have to do the rescan from within the mythtv-setup Graphical utility.  This will be difficult to do over a ssh connection and ( I assume) a windows PC.
> >
> > Regards
> I routinely use my Macbook pro to ssh -Y into my mythtv-backend to run
> mythtv-setup.  So that should work for this.
> As to Windows?  What's that?  :-)  When I turned in my company Laptop
> when I retired, that's the last time I used Windows.  I can run Windows
> XP in a Virtual machine on my Ubuntu desktop or Macbook, but why. :-)

About mythtv-setup creating new channels or updating old channels.

In a nutshell it works like this (as I understand it).
A channel found in a scan is considered an old channel if the
transport/multiplex has the same frequency and if the ATSC major and
minor channel numbers are the same. In that case the existing
callsign, channel name etc are replaced by the values from the scan
but the xmltvid is preserved.
This means that if channels, even if they keep the major/minor
numbers, are on another multiplex after the update they will be seen
as new channels.
The callsign is relevant for programming/scheduling/recording but it
is not used by mythtv-setup for identifying a channel so there is no
need to edit it before doing a scan.

If this is not the way that it should be then it is always possible to
create a ticket with a description on how the channel update behavior
should be. The question of what identifies "the same channel" needs to
be addressed there.

Note that I have not tested this because I do not live in ATSC land,
but with DVB it works along the same lines, with channels identified
by network ID and service ID.
- channelinfo.cpp:445 function ChannelInsertInfo::IsSameChannel
- channelimporter.cpp:968 function ChannelImporter::GetDBTransports

Success with the update!

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