[mythtv-users] channel musical chairs

[Stephen Worthington]

On Sat, 18 Nov 2023 20:55:37 -0800, you wrote:

>Thank you, Stephen and Gary, for all the info.  If I don't run a
>rescan or use my external program to make modifications, I'm still not
>clear on what happens.
>
>I have been assuming that the program guide, backed by info from SD,
>is accurate (except for glitches, and perhaps delays catching up to
>channel redefinitions).  Accurate means the programs listed on, e.g.,
>4.3 are what I'd actually see if I tuned to 4.3.  Less importantly, it
>means the callsign and icon are accurate.  But is any of that true?
>For example, if the xmltvid is not updated, and if that's the key for
>matching SD, then I'd be getting a listing for something that might be
>showing on a different channel, or not at all.  @Gary says that
>sometimes SD will continue to use the same xmltvid, in which case a
>mismatch on that would not be a problem.  But that also means that
>sometimes it changes, and then what happens in mythtv?

Sorry, I can not help with SchedulesDirect as they do not do New
Zealand EPG.  I believe it is possible to get channels created from
the XMLTV EPG data, rather than from a channel scan.  So should you be
doing that instead of scanning?

>The interpretation of "same channel" as "same callsign" explains why
>sometimes I will try to limit recording to, e.g., 11.1, and I end up
>getting double recordings on 11.1 and 11.3: they have the same
>callsign. (Actually, slightly different: "KNTV HD" vs "KNTV-HD".  But
>I think I've had this problem with that pair).

With callsigns there is no such thing as "slightly different" - any
difference at all means it is a different channel.  There is no
matching for "similar" callsigns.

I have a channel that is on two sources where I often see that the
upcoming recordings list is showing that it will record from both
sources.  But in fact it only records from the higher priority source
(free-to-air DVB-T).  I think this is a bug, but not a bad one as it
is only a display problem.  And very occasionally, I have had both
channels recorded.  I think, but have not confirmed, that it has
happened when the DVB-T tuner was taking a long time to tune, so the
recording from there was not marked as started, and the DVB-S2
recording was then also started.

>BTW, the changes to virtual channel 4 are definitely part of an ATSC
>3.0 move.  And 44.5 already has a date/time in channel.deleted.  I
>used the Services API Channel/RemoveDBChannel to do that, which must
>mean it didn't get deleted on its own or via an update from SD.

Any channel deletion using the proper MythTV tools (the API or
mythtv-setup) will mark the channel as deleted if there are any
recordings that match the channel.  If there are no matching
recordings, I am not sure of the exact process - it may just be marked
as deleted in the same way, or it may be completely removed from the
channel table.  In any case, there seems to be a housekeeping task
that runs regularly (daily?) that will completely remove old channels
when there are no more matching recordings.

The channel scan process now uses the same delete channel procedure as
manual deletions - it will mark channels as deleted if they disappear
from their source.