[mythtv-users] Sources and inputs

[Nick Morrott]

On 08/07/2008, Chris Dennis <cgdennis at btinternet.com> wrote:
> Hello MythTV People
>
>  My MythTV backend has two DVB-S tuner cards, and a twin DVB-T card,
>  giving me four inputs in total.
>
>  Having read all the documentation I can find, and tried various
>  combinations of settings, I can't work out how many Video Sources I
>  should set up.
>
>  DVB-S and DVB-T carry different channels (with some overlap), but the
>  only workable xmltv source of listings is tv_grab_uk_rt.
>
>  I've set up a separate channel listing file for DVB-S and DVB-T, i.e.
>  the files with lines like   channel cbeebies.bbc.co.uk
>
>  channel channel5.co.uk
>
>  It seems sensible to just have one Video Source defined in mythtv-setup
>  for DVB-S, and one for DVB-T, because they refer to a single source of
>  information.  But on the other hand, 'Video Source' also seems to mean
>  the same thing as 'Input Card' when it comes to switching sources in the
>  front-end menu.  If I only define one Video Source, I can't use 'Switch
>  Source' from the Live-TV menu.
>
>  What is the best way to set this up?

I would define 2 video sources using the tv_grab_uk_rt grabber, and
run mythfilldatabase manually for each videosource. A video source
should contain the channels available on a /card input/ (or card
inputs if you associate the same video source to multiple card
inputs). Note that multiple videosources can use the same source of
listings data (for example you have an analogue tuner, a DVB-T card,
and Sky Digital) but the channels configured on each videosource will
be different for each platform.

As long as the 'same' channels (in UK parlance) have the same XMLTV
IDs associated with them, they will be treated as identical to the
scheduler, allowing scheduling of programmes on the channels common to
each videosource on either DVB-S or DVB-T.

Current DVB-S (since the EIT patches were committed to -fixes) and
DVB-T EIT listings data is now pretty good, so it is an option, but
there can be differences between the listings for the same channel
(ITV Central for example) between the two platforms which confuse the
scheduler enough to wreak havoc with duplicate detection. Using a
common listings source for each videosource (such as XMLTV) gets
around this issue, but adds the requirement of an internet connection
to the mix.

If you run the current development version of XMLTV (a new 0.5.52
release is imminent, however) you will be able to try out my recent
work on adding lineup support (basic at the moment) to the grabber.
You can choose Freeview and FreeSat platforms when running
configuration, and this will automatically filter the list of
available channels to those available for the chosen platform from the
uk_rt grabber. Choosing 'all' to the first channel will instantly
create your config file containing all channels on the platform*. It
still doesn't enable automagical channel numbering in MythTV, but that
is on the horizon with the XMLTV lineups project.

* It is possible to use a single XMLTV file containing all channels
you can receive on all sources, and run mythfilldatabase (with the
--update switch) once for each source pointing to this file. It is
also possible to use both XMLTV and EIT data on the same source to
cover cases where the XMLTV grabber does not provide listings data for
certain channels.

Nick

-- 
Nick Morrott

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