[mythtv-users] cards vs sources vs inputs confusion, problems and possible bugs

R. G. Newbury newbury at mandamus.org
Thu Dec 3 18:24:40 UTC 2009

Nick Morrott wrote:
> 2009/12/2 Petr Stehlik <pstehlik at sophics.cz>:
>> George Mari píše v Ne 29. 11. 2009 v 10:26 -0600:
>>> Assuming your two cards are both receiving from the same service
>>> provider, I'm also pretty sure you should not setup two independent
>>> sources, as you will run into the problems you mentioned.
>>> I have 2 cards also - one receives OTA broadcasts via antenna, and
>>> another receives analog video from a satellite settop box.  I have one
>>> source, but I have two lineups with Schedules Direct.  Most of the OTA
>>> channels are duplicated on the satellite lineup, and I just associate
>>> the OTA card with the OTA lineup for my region from Schedules Direct,
>>> and the Satellite lineup is linked to my old analog card.  It all just
>>> seems to work fine.
>>> If you post who your satellite service provider is, I'm sure someone
>>> else on the list can help you out.
>> It's Astra 3A but I don't think it's important. I am more interested in
>> the "wiring" inside of the mythsetup (Input Connections) when one card
>> is more capable than the other one so it can receive more channels. If
>> there is just one video source then I don't quite see how to prevent the
>> less capable card tuning to all the channels in the video source.
> You will need to configure two video sources, and configure each of
> the card inputs separately on the Input Connections screen.
> If one input receives a subset of channels compared to another input
> (even if the channels received on both inputs are transmitted using
> the same method - analog/DVB-T/DVB-S/ATSC/QAM etc) you need to ensure
> that you have separate video sources that contain only those channels
> available for the intended tuner. This will prevent MythTV from trying
> to schedule recordings or watch LiveTV on channels that are not
> available on an input.
>> I should try changing it to one source and see for myself but before
>> I'll break all the stuff (tuning the sat channels back will take me
>> several hours of manual work) I thought I would ask here.
> Good idea. I comes up fairly regularly, but sitll requires a fair
> amount of configuration, especially for non-Schedules Direct users.
>> Anyway, I am going to buy some DVB-T tuners that will further complicate
>> the setup (they can receive only a subset of the DVB-S channels).
> Again, configure a new video source for just the DVB-T channels. If
> all DVB-T tuners can receive the same group of channels, you only need
> to configure a single video source and connect it to all of the DVB-T
> tuners in mythtv-setup.
>> My goal is still the same: in LiveTV pressing a certain channum should
>> always find a free tuner that can tune and play that program (no matter
>> if its DVB-S2, DVB-S or DVB-T). Also when browsing across all the
>> channels on all tuners pressing the OK on any channel should again find
>> a free tuner and tune&play that. So far it does not work that way and
>> the question remains if this is a bug in configuration or in Myth
>> itself.
> For scheduling:
> MythTV needs 'equivalent' channels (broadcasting the same station)
> available on all video sources to have the same callsign in order to
> make intelligent scheduling decisions across tuners. Obtaining
> listings from the same source (SD/XMLTV/EIT etc) for all video
> sources/channels will ensure that the scheduler uses the same
> programme data during scheduling runs. Mixing listings from different
> sources for 'equivalent' channels can result in unexpected behaviour.
> For LiveTV browsing and EPG viewing:
> Giving 'equivalent' channels on all video sources the same channel
> number (channum) and name will group channels together so that MythTV
> can 'find' the channel on all tuners and allocate it to the next best
> LiveTV tuner if required. It will also hide multiple copies of the
> 'equivalent' channels which can greatly condense the EPG.
> Cheers,
> Nick
To follow on from Nick's explanation and to make things clear,

mythtv uses chanid internally as a key for ONE channel.
mythtv uses the callsign to determine if chanid's are equivalent for 
recording scheduling, and
channum can be set to whatever WE want so that the channel shows up in 
the EPG where we want, and using a name/number we recognize.

You can use priorities to differentiate between channels which have the 
same channum for recording purposes.
But you MUST use separate sources for different channel groupings 
notwithstanding that some channels are available on more than one source.

I'm not sure that you can exactly do what you want, as I am not sure how 
  the code collapses 'equivalent' channels, as Nick notes. However, you 
can probably get very close to the desired state if you give the 
equivalent channels near equivalent channum designations.

For example, if you get   2,4,6,8,10 from OTA and 6,8,10 from digital 
cable as 206,208 and 210, giving the latter a channum of 6A,8A and 10A 
would list them in the EPG below/above their equals. Internally, their 
chanids differ and myth would know how to tune them accordingly. And an 
in-use channel/tuner combo would show in the EPG.
Not QUITE what you want, but close. Then again, do a backup of the 
database, and then adjust the callsigns and channums and see what 
happens. Myth may collapse the listings but still know that more than 
one tuner is available for any given channel. Let us know how it goes. 
Report here and make changes to the wiki, please.


         Please let me know if anything I say offends you.
          I may wish to offend you again in the future.

          Tux says: "Be regular. Eat cron flakes."

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