[mythtv-users] Help on Video Sources

[Bruce Markey]

Roger James wrote:
> My system has two digital capture cards, and one analog one.
> 
> I currently have two video sources defined both of which use 
> tv_grab_uk_rt to get listings from the radio times web site. One fetches 
> data for the four main UK analog terrestrial channels, the other for the 
> UK digital terrestrial channels which include the same four channels as 
> the analog plus a number of extra channels.
> 
> The four main channels each appear twice in my channel table (in the 
> database) with different channel ids, different names, but the same 
> callsign and channel number.

If that is true, then the EPG should only show one line for
each callsign/channum.

> I used to be able to operate with one video source and one entry for 
> each of the main four channels in the channel table. This one entry 
> containing both DVB and analog tuning information. However these ceased 
> to work some time ago and I had to change to my current two video source 
> setup.

Inputs are associated with sources including all the channels
associated with that source. Each row in the channel table is
associated with one source. What you seem to be trying to imply
has never been true. You would always need one source to define
a set of four channels and a different source to define a larger
set.

> The downside of this setup is that I end up with duplicate program 
> information in the program table for the four main channels. Each 

Non-issue. This is a few tens of K on a system that records
video by Gigabytes per hour. Don't make be do a bar graph ;-).

> program on these channels appears twice but with different channel ids.

"Appears" is a bit vague. Both the EPG and the proglist (used
for search results and upcoming lists) will show one line or
entry for the callsign/channum regardless of there being more
than one chanid for that showing. If the channum is different
or a different variation of the callsign was used, then it
would show both.

> I am about to connect a satellite box to the composite video input on my 
> analog capture card. If I set this up the same way I will end up with 
> another video source which duplicates the large number of channels 
> already on the digital terrestrial source and adds some more unique ones.

The volume of data is insignificant. Many people have hundreds
of channels BTW. Even though you see that you will have the
same listings for the same station on different source/channels,
this is not always the case and listings must be associated
with specific channels (see attached).

> I would like to avoid this duplication if I can. I am not convinced that 
> my currently setup always correctly identifies that the same channel is 
> available from multiple sources even though the callsign and channel 
> numbers match. It only seems to schedule between my two DVB digital 
> cards and never schedules anything on the analog card, but I have never 
> fully verified this.

You could go to your EPG and press "R" on three overlapping
shows in less time than it took to type this.

> Can I attach all the inputs to one video source? If I do this will 

If they are different sets of channels then no.

> detection of the availability of the same channel (identified by 
> matching callsign and channum) on different inputs work correctly? If I

Displaying one row in the EPG for matching callsign and channum
should already work. If not they may not actually match.
 
> set use DVB EITS on the video source will this work correctly and be 
> ignored for none DVB inputs?

Nope.

> I realise that many aspects of this question have been covered before, 
> but any suggestions will be gratefully received.

I started writing a section for the HOWTO to cover issues with
multiple sources, channels and inputs. Here is an awkwardly
written first draft to touch on the key points. However,
I can see this would be baffling to a new user and needs a lot
of work to make it more digestible.

--  bjm

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