[mythtv] [mythtv-commits] Ticket #3299: Allow mulitple video sources to reference single Datadirect lineup

[Nick Morrott]

On 18/04/07, Michael T. Dean <mtdean at thirdcontact.com> wrote:
> On 04/12/2007 04:36 PM, MythTV wrote:
> > #3299: Allow mulitple video sources to reference single Datadirect lineup
> >
> >  When multiple sourceid's are associated to a single datadirect lineup,
> >  such as is the case when receiving programming from multiple satellites
> >  for a single provider, mythfilldatabase would deselect almost all channels
> >  from the datadirect lineup. The process would essentially remove all
> >  channels not associated to the current sourceid. When the second sourceid
> >  is processed, all channels from the first sourceid would be deselected.
> >
> >  This problem is also alluded to here: #3295
> >
> >  The attached patch will enable updates to the datadirect channel list
> >  based on lineupid rather than sourceid.
>
> I spent a lot of time looking over this patch and its affects on
> MythTV/mythfilldatabase today.  The patch looks good to me, but I've
> tested it only in my mind, though. ;)
>
> However, I recommend that this patch is not committed until a further
> modification is made.
>
> Currently Myth is designed around the idea that each video source gets
> listings from a different "listings" source--in other words, it assumes
> that the something about the grabber configuration (or, in the case of
> DataDirect users, the lineup) is different for different video sources.
> Therefore, mythfilldatabase currently downloads the required listings
> data once for each video source and does not provide any mechanism by
> which to reuse that data (even if the lineup is being reused).
>
> Applying this patch would encourage users with overlapping channels on
> multiple video sources to consolidate their (small) separate lineups
> into one (larger) lineup--if for no other reason than to only have to
> manage a single DataDirect account or to avoid the worry of using
> listings from a neighboring zip code's provider.  Since the
> "consolidated" lineup's listings data would still be downloaded once for
> each video source that uses the lineup, encouraging users to create
> larger lineups and reuse them on several video sources is not
> appropriate without some mechanism for caching the data.

Reading this with interest and having a UK XMLTV perspective (and
getting my wrist slapped for opening #1125) there are two ways I can
think of for caching XML data for XMLTV users:

i) use the http::cache module

This caches individual files downloaded by a XMLTV grabber (14-days
per channel in the case of the uk_rt data currently) and if another
video source config requires them, will pull them from the local cache
instead of hitting the source server again.

ii) run the grabber manually with a config containing *all* of your
channels, then either perform some XML-fu to parse out the data into
XML files for each video source, or configure mythfilldatabase to use
the single XML source file (which I alluded to in #1125) for each
video source.

Either method will cut down the amount of duplicate data downloaded
from the listings server, sometimes by significant amounts if channel
overlap across sources is large.

Nick
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