[mythtv] Channel Management Ideas and Plans

David Engel david at istwok.net
Sat Apr 13 16:47:35 UTC 2019

On Sat, Apr 13, 2019 at 12:39:44AM +0000, Gary Buhrmaster wrote:
> On Fri, Apr 12, 2019 at 8:24 PM David Engel <david at istwok.net> wrote:
> > I have about 90% of an option 3 coded and tested.  It creates new,
> > recordedchannel (for recordedprogram) and oldchannel (for oldrecorded)
> > tables.  The last remaining part has to do with icon handling.
> > Becuase the icon path is not part of the Program/RecordingInfo object,
> > it is fetched on demand using ChannelUtil::GetIcon() which blindly
> > uses the channel table.  It needs to be modified to conditionally use
> > channel, recordedchannel or oldchannel as appropriate.
> One of the problems, which I believe you are aware of,
> with icons is that (at least with US cable and satellite)
> that the proper icon (and the callsign and name) for
> channel 123 may be for the USA network on 2017/04,
> and be the TNT network in 2019/03 (made up networks
> and dates, of course).  So if the icon is important, you
> have to copy the info at the time of record.  Even if
> the videosource still exists, and is still being used,
> the actual "station" on the "channel" may now be
> different.
> Without doing much evaluation, I think the only way
> that a "deleted" flag makes a bit of sense is that if
> every update to a channel makes the current channel
> "deleted", replaced whatever is the new values may
> be and (of course) a new chanid, which may have
> implications of existing guide data.

I'm very aware of the issues.  I didn't want to get bogged down in the
minutia of changed channels versus new channels.  Ultimately, that's
the user's decision.  But since you ask, I'll give my personal opinion
with a few examples.

When the callsign changes from TNN to SPIKE to PAR, those are new
channels.  The existing channel should be marked as deleted and a new
channel with a new chanid should be added.  Old recording will
continue to reference the old channel as long as the exist and new
recordings will reference the new channel.

When the Cable Co. moves ESPN from channel 123 to channel 456, that's
not a new channel.  The existing channel is update and life goes on.
It won't bother me in the least that recordings really done on channel
123 might now show as done on channel 456.

When Outdoor Life Network changes its name to OLN or Science Fiction
changes to SYFY and neither substantially changes their programming,
those probably aren't new channel either.  Someone else might feel
differently and they're free to do a delete old/add new if they like.

I very much like my new proposal for keeping the simplicity of a
single table with a single column controlling visibility features
and also has the ability to preserve historical entries when they
are desired.

David Engel
david at istwok.net

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