[mythtv-users] Sources and inputs

Chris Dennis cgdennis at btinternet.com
Tue Jul 8 20:33:37 UTC 2008


Thanks for your comprehensive reply Nick.  It took me a while to get my 
head around it all, and raised more questions I'm afraid.

Nick Morrott wrote:
> 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. 

Do you mean one videosource (as defined in the videosource table) for 
DVB-T and one for DVB-S, or two for each?

> 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.

That's useful to know.
> 
> 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.

The internet connection is not a problem.  Are you suggesting that I 
should use a single XMLTV listings file (with 'channel 
cbeebies.bbc.co.uk' etc.) for both DVB-S and DVB-T?  Re-reading the 
previous three paragraphs confirms that you are suggesting that.  Are 
there any disadvantages to that approach?

> 
> 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.

Is there more information on that project somewhere?  I've cobbled 
together some scripts of my own for assigning channel numbers and 
associating xmltvids with channels.  I'm only running xmltv 0.5.49 
though in the standard MythBuntu setup at the moment.
> 
> * 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
> 

On a related theme, what does mythfilldatabase do apart from retrieve 
program listings?  I understand that it changes channels and icons if it 
is run without the --update option.  Is this documented anywhere?

cheers

Chris
-- 
Chris Dennis                                  cgdennis at btinternet.com
Fordingbridge, Hampshire, UK


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