[mythtv-users] 1 CableDigital Lineup available to chose but need 2 sources from it

[Daniel Kristjansson]

On Wed, 2007-10-17 at 10:03 -0400, Michael T. Dean wrote:
> OK.  But the point is that when selecting the "same channel" on multiple
> SD lineups, mythfilldatabase does not reuse the listings data downloaded
> for that channel from the first lineup (
> http://www.gossamer-threads.com/lists/mythtv/users/295993#295993 ). 
> Even though David has two separate lineups, and it looks like Myth is
> able to pull listings for one from another, both /are/ being
> downloaded--they're just both being downloaded at the same time before
> the first video source is processed.

It depends. If they really are the same channel, i.e. with the same
station id, then the listings for the channel are only contained
once in the XML we get from TMS. If they are almost the same, i.e.
with a different station id, then the program descriptions that
are in common are only downloaded once but we do download a very
similar map of stationid+stationid->program mappings.

> > Using multiple similar DataDirect lineups used to be very inefficient
> > in the labs days but we do a lot better job at caching now.

> Right.  I wasn't trying to say that using different lineups is
> inefficient and should be avoided.  I was actually trying to show why
> it's more efficient to use the new "caching" ability than it would be to
> get SD/TMS to allow users to create multiple lineups using the same
> provider (
> http://www.gossamer-threads.com/lists/mythtv/users/295989#295989 ). 

This is definitely true. If you use different accounts there is no
reuse of data between the lineups.

> I was trying to say that we can only reuse the program listings data if
> the lineup is shared by multiple video sources and that the whole reason
> you added this ability to cache the data when using the same lineup for
> multiple sources is efficiency.

This is not correct. If there are two lineups in SD with the same
stationid's the TMS XML format only contains one entry for each
program listing. There are two lineup definitions in the file but
these are a trivial portion of the file. You're right about the
reason I added the caching, it was to allow the same SD lineup to
be used for multiple MythTV Video Sources efficiently+, but it also
has a great side benefit of reducing the amount of data we download
in any "multiple lineups on one account" setup.

-- Daniel

+ This could actually be done with older versions of MythTV, but it
  was very inefficient to do so.