[mythtv-users] DVB re-scan and XMLTV EPG?

[Mike Perkins]

On 28/01/15 09:08, Philipp Hahn wrote:
> Hello,
>
> I recently relocated and finally had to reset the DVB scan and channel
> setup. I dreaded that moment, because in the past I always lost the
> information about xmltv IDs and channel icons - This time I lost them
> again, so I'd like to ask what I'm doing wrong or where I didn't grasp
> a concept yet:
>
> I live in Germany, use DVB-C and get my electronic program guide
> (="Video Source") from epgdata.com through XMLTV's "tv_grab_eu_epgdata".
>
> 1. What is a "channel lineup"? If my understanding is correct, it's the
> "numbering" of channels. From my experience, in Germany there is no
> fixed line-up and a station - for example "Das Erste" - is on channel X
> in city 'x' and on channel Y in region 'y'. That lineup is provided most
> often on paper or as PDF, but there exists no electronic version.
> In the past I always re-arranged the channels so that "Das Erste" is
> always on channel number '1'.
>
> 2. As the "Channel Name" and "Channel Callsign" don't match the names
> fom epgdata.com, they're not associated with each other automatically.
> So I end up editing all channels and have to assign the right xmltv ID
> to get the EPG working.
> This is further complicated by the fact, that the same channel is
> sometimes included multiple times in different transport streams with
> slightly different names, that is "Das Erste", "Das Erste HD", "ARD":
> They all provide the same program, but are allocated 3 programs in
> MythTV and I have to manually merge them to at least have the same
> "Channel Callsign", so that the scheduler can pick the best transport
> (when recording multiple programs as the same time).
> In the past I always did that using SQL directly, because it was no fun
> to update 60+ channels each time I had to do a re-scan.
>
> 3. Same for the channel icons: That information is always lost and I
> have to re-assign the correct icons.
> Doing that with SQL directly is my time saver, as
> <http://www.mythtv.org/wiki/Networkiconmap_table> and
> <http://www.mythtv.org/wiki/Callsignnetworkmap_table> are always empty
> for me.
>
> 3. My feeling is that the MythTV developers are from "North America"
> mostly and there the EPG providers like DD and SD also provide that
> additional data and therefore they never have to fiddle around with
> xmltv IDs and therefore "deleting all capture devices and do a re-scan
> just works".
>
> 4. Can the EPG data provided internally within the DVB stream be used to
> augment the EPG data provided externally from epgdata.com? The last one
> provides better description, but is only updated once per day and as
> such is prone to time changes caused by major events.
> <http://www.mythtv.org/wiki/User_Manual:MythTV_structure#Video_sources>
> talks about "Transmitted guide data (EIT) can also be used as ... a
> supplement to the other sources if it is available.", but what does that
> mean exactly?
>
> Thank your for your time and that great piece of software called MythTV.
>
I think, as another responder says, that the setup arrangement suffers from the 
fact that the originators of mythtv are North-American based and they have used 
their own terminology in naming parts of the process.

Much of what they do doesn't really mesh with practices in the rest of the 
world, as you have discovered.

A "channel lineup" is simply a list of the channels you are able to receive by 
using one particular tuning method. That might be Cable, Over The Air (OTA), 
Satellite, the Internet or even some other method. This list represents a Source 
and has consistent tuning information designed to find and record from one 
"channel" in that "lineup".

That is why the tuning information is kept separate, although that may change in 
the future. I myself have three tuners using the same lineup and setup allows me 
to link them to the same lineup.

In North America, they call a "Multiplex" a "Channel" and a "Channel" a 
"Subchannel", this is because of the way that they number their channels. It can 
make posts to this list interesting to decipher sometimes.

Items like "Channel Name", Channel Callsign" and Frequency have different 
meanings outside North America. In the UK, where I am, we don't use callsign but 
just Channel Names. However, scheduling uses Channel Names in particular ways 
that may not be helpful to you. Here Frequency will be filled with the Channel 
Number and used for tuning.

I should note that in your example above "Das Erste" and Das Erste HD" are 
*different* channels! One is Standard Definition and the other High Definition. 
By choosing to give them sthe same Callsign you remove the ability to select 
which format will be recorded, not to mention how much disk space is used!

In the UK The HD channels are usually the exact same content as the SD channels, 
but *not always*. Unless you know this to be true in your location, you should 
always consider them to be distinct.

-- 

Mike Perkins