[mythtv-users] Anyone with a MythTV and Free-to-air satellite setup in the United States?

Another Sillyname anothersname at googlemail.com
Fri Jul 13 06:38:15 UTC 2012

On 13 July 2012 01:24, Karl Dietz <dekarl at spaetfruehstuecken.org> wrote:
> On 13.07.2012 01:20, Robert Kulagowski wrote:
>> On Thu, Jul 12, 2012 at 4:36 PM, Amy Overmyer<aovermy at yahoo.com>  wrote:
>>> on a traxis, you would need a bunch of channels, as many as the traxis
>>> could
>>> see (or as many as you want to record/watch) in a database with channel
>>> numbers of some sort (many people choose numbers like 83_1, 83_2...93_1,
>>> 101_1 etc. based on the satellite they're pointing at).
>> If there are 20 available FTA on a particular transponder, it looks
>> like a combination of polarity, frequency and vpid are unique. But
> a possible unique key is constellation/position, frequency, polarity and
> program_number (instead of vpid, as multiple services can share the same
> video stream. Its useful when you switch out for local programmes and
> join back for shared programmes. Its called dynamic PMT and common in
> Europe)
>> that's a lot of typing! Do people just let their receivers run a scan,
>> then assign "1", "2", etc locally, so that possibly _my_ 101_1 may not
>> be the same as yours?
> Some satellite packages sent out logical channel numbers but I have
> configured my cable / terrestrial backend with manually selected
> channel numbers and call signs. (so one station gets the same number,
> no matter if its HD/SD or DVB-C/DVB-T)
> If you do nothing you'll get numbers based on the transmitted program
> number and video source id.
> I don't think you'll get nice LCN for US FTA ;)
> There are scripts for UK floating around that set nice channel numbers
> (and other properties) based on service name or
> original_network_id + service_id. Providing such a script for US FTA
> might be an idea.
> Regards,
> Karl
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Can I just add my 2c to this conversation although I'm in the UK.

As may have been covered previously in this conversation but I'll
recover just for clarity......

There are TWO important numbers regarding channels

chanid which is set automagically by the system during a scan based
upon the video source (as defined in mythtv-setup)

channum which is initially defined based upon chanid but is a 'soft'
number that can be changed.

Let's say you have 3 sources.

Source 1 = Terrestrial DVB-T(2) which is supplied to your TV card via
your standard antenna.  Let's call this DVB-T.

Source 2 = Satellite xx1 DVB-S(2) which is supplied to your TV card
via your motorised dish. Let's call this xx1.

Source 3 = Satellite yy2 DVB-S(2) which is supplied to your TV card
via your motorised dish.  Let's call this yy2.

Firstly (I know this sounds silly but it is a trap many users fall
into) make sure that your card devices load in the same order every
time when the machine boots up.  The best way to achieve this is
blacklist them and then at startup have a script that loads them in a
specific order with a small sleep between each load.  If this is not
done cards can load in a different order based upon cold or warm boots
and myth will not detect the wrong DVB-S device is now occupying the
/dev/dvb/ slot where it expects a DVB-T device.

So you now have you three video sources defined, if you then scan each
source you will end up with a populated database table called

In mythconverg.channel the chanid for a channel is set during the scan
based upon which video source was used, for example let's say in the
UK you ONLY used a single source and that source was Freesat satellite

When you did your scan the BBC HD channel would be set a chanid of
6940 as that's the number that would get assigned by the satellite
source, have a look here.


Go down to BBC HD channel on 10847 V on transponder 50 read across to
BBC HD UK and you'll see in the SID (service identifier) column the
value of 6940.

This value would be assigned by myth to be the channum number in
mythconverg.channel (channum can be changed as we'll come onto).

However let's say our system was a dual DVB-T and DVB-S system with
the DVB-T terrestrial channels being scanned first.  Now when we do
our scan of DVB-S channels the BBC HD UK channel could well have a
chanid of say 8940 (adding 2000 to the SID value) to attempt to shift
all the new channels into a new non conflicting range, the channum
would still be assigned based upon the chanid and any channum
conflicts would be notified during the scan.

Taking it a stage further let's say you scanned DVB-T first, then
another satellite feed, then the feed that supplies BBC HD you might
now find that BBC HD UK has a chanid of 10940 (adding 4000 to the
SID), hopefully this makes sense.

So going back to the earlier example with the 3 feed setup of DVB-T,
xx1 and yy2.  As you do each scan the database gets populated with all
the channels and if you look at the mythconverg.channel table you can
see the chanid, channum and source values for each channel.

The one variable you can change here without too many problems is
channum.  This is your own 'soft' channel number that you can set your
own preferences for.

what channels you want to assign to what channum values and then if
needs be get 'rid' of any conflicting channum channels by changing
their channum value to some ridiculously high number such as
999934838434xxxx to get it out of the way.  Then to further clarify
what you actually show ONLY make the channels you want visible.

As touched on by someone else there are scripts that allow you to
setup your channels the way you want
http://www.mythtv.org/wiki/UK_Channel_Assignments which should give
you some ideas to work from.

I would suggest that the way to configure your system is setup your
DVB-T feed as the first source you configure and ensure that this
card(s) is the first one setup in your system (it's just easier to
visualise if the physical cards match their virtual source priority).
Scan these channels first.

Then setup your second source and scan it, then your third source and
scan that.  If you're using a motorised dish to feed two sources into
one card I'm not sure exactly how you'd go about programming the ir
changer to ensure the dish auto changed the satellite it's pointing at
but I'm sure that someone here will know.

Hope this helps and dual Terrestrial/Satellite systems are reasonably
common in the UK so what you're trying to do should have been done
before somewhere.


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