[mythtv] [mythtv-commits] Ticket #3418: [13136] prevents seeing channels with duplicate callsigns

Nick Morrott knowledgejunkie at gmail.com
Tue May 8 10:22:33 UTC 2007

On 08/05/07, Simon Kenyon <simon at koala.ie> wrote:
> Daniel Kristjansson wrote:
> [lots of good stuff snipped]
> IMHO if the core developers are confused by
> channel/frequency/callsign/multiplexes/multiple programming stream feeds
> then what hope is there for us mere mortals.
> being from europe and not using callsigns (well not for the last 50 odd
> years or so) and having multiple methods for receiving that same
> programming, how should i/we set things up.
> as a concrete example:
> i have three different feeds of BBC1 (Northern Ireland)

Really a -users question so CC'ing -users too if you want to carry
this specific conversation on there, but....

Are you are using the tv_grab_uk_rt feed for this example/all of your channels?

> i have a sky digibox
> i have two other STB which can receive it because it is free to air
> i have two DVB-S cards
> at the moment i have them set up as separate entries in the EPG (51, 143
> and 4001)
> should they all have the same "number" in the EPG?

If they are using the same listings from the Radio Times (For BBC1 NI
- northern-ireland.bbc1.bbc.co.uk), configure them with:

i) the same XMLTVID
ii) the same CALLSIGN and NAME
iii) the same CHANNUM

Having the same listings for each instance of a channel across video
sources means the scheduler has optimum information to schedule as
efficiently as possible. You *could* mix and match listings sources
for the same channel on different sources - use XMLTV for the Sky/STB
channels, and DVB EIT for the DVB-T/S/C - but this usually means
listings information for the same programme is different depending on
video source - which gives the scheduler significantly sub-optimum
scheduling capabilities, especially when using duplicate matching with
subtitle and/or description.

> i don't even know what to call this number. is it a channel number or what?

The 3 different numbers your channels above currently have displayed
in the EPG (51,143,4001) are what MythTV calls the channel number
(channum). This is what you key in to change channel when watching
LiveTV, and what you will see in the EPG and upcoming recordings

If you only want one entry for the channel in the EPG - because it is
the same on all sources (Sky/STB/DVB-S) - you have make sure the
channels have the same callsign and channum.

This is how I have all of my channels configured in the UK, and how I
ensure the scheduler can schedule across the same channels on
different card inputs/video sources.

The other 2 important numerical channel settings you may see mentioned
are CHANID and FREQID. CHANID is a unique identifier for each channel
in MythTV, used internally for tuning and scheduling, so MythTV knows
exactly which channel is being used. FREQID typically contains tuning
information for analog tuners (the UHF channel number) and for
channels tuned externally via a script (the channel number the tuning
script should turn the cable box to when mimicking the remote

Digital tuning via DVB multiplexes is taken care of with another field
in mythconverg.channel and the mythconverg.dtv_multiplex table - but
this is beyond the scope required for setting up channels for display
and scheduling.

The Radio Times listings support the key regionalised channels -
BBC1/BBC2/ITV1 - so as long as user uses the correct XMLTVID initially
and uses it consistently across video sources - everything should be
gravy (paraphrasing Jarod).

I've got plans to try and get this sorted once and for all over the
next few months in both the XMLTV project (add channel/platform
support in the DTD) and within MythTV (to enable users to add country
based platforms and channel lists), health and relevant knowledge

MythTV Official wiki:
MythTV users list archive:

"An investment in knowledge always pays the best interest." - Benjamin Franklin

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