[mythtv] mythfilldatabase, Schedules Direct, json and xmltv

Gary Buhrmaster gary.buhrmaster at gmail.com
Mon Jul 18 14:54:56 UTC 2016

On Sun, Jul 17, 2016 at 8:02 PM, Peter Bennett <pgbennett at comcast.net> wrote:
> and provide a better way of selecting channels.

btw, part of the issue here is the very real difference
between stations (scheduled content) and channels
(methods of delivery).  xmltv calls stations by the term
channel which sometimes leads to confusion, and
their guide data is organized by station (not channel),
although, again, xmltv uses the term channel.

And while there are some for which there is a one-to-one
(and only one-to-one) mapping between a station and
a channel, that is not correct in the general case(*)(**).
And while the xmltv use of station can be coerced into
sort of providing the information one might like for
MythTV, doing so sometimes generates validation errors.

There was some discussion (some time ago) on the
xmltv lists to attempt to consider how to address this
in order to provide applications additional information
(i.e. to provide info regarding channels used for delivery)
to use to better manage application lineups.  I do not
believe there was any consensus on ways forward.
There were, as I recall, three different proposals, each
with slightly different approaches.  The tv_grab_na_sd
grabber implements (or tries to implement, there is
no formal dtd or validation) the approach with --get-lineup
that dekarl proposed.

MythTV supports the differentiation between a channel
and a station, and there are mappings from xmltv
format to MythTV format, but they are not perfect and
that, understandably, frustrates some people who want
things to just work and do not want to spend hours
inside the channel editor.  I can fantasize that the work
on the web based setup (including the channel editor)
may make it less painful, and where, I am guessing,
future work should be focused (is web based setup
still in the v29 intended deliverable?)

(*) Many stations are indeed delivered on more than
one channel.  The classic case is broadcasting the
same content on a different transmitter (repeaters
or translators).  And on cable systems the same
station may be on multiple channels in order to
provide groupings for the <up><down> channel
surfers (all latino channels together, and also all
local channels together, and all news programs
together.  One station may be all of those at the
same time).

(**)  and there is the very special case where a
channel broadcasts one station for one part of
the day, and another at another time.  Yes, those
do (or at least did) exist.

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