[mythtv-users] feedback for feature request: ability to define input connections as inactive

R. G. Newbury newbury at mandamus.org
Fri Mar 9 18:05:59 UTC 2007

ryan patterson wrote:
> On 3/8/07, Joe Harvell <jharvell+lists.mythtv-users at dogpad.net> wrote:
>> I recently filed a bug report (http://svn.mythtv.org/trac/ticket/3093)
>> having to do with input connections with no video sources.  The bug is
>> that the frontend crashes when you try to access the program guide if
>> there are no input connections associated to video sources.  The
>> response I got was that the frontend should not crash, but instead, the
>> program guide should show nothing.  I argue that as long as you have
>> channels defined you should be able to look in the program guide and
>> make schedules.
>> Another problem associated with input connections is that if you have a
>> capture card defined, but none of that specific capture card's input
>> connections is associated with a video source, the backend complains
>> that init of that card failed.  Then later, the backend crashes if you
>> look at "Tuner Status" from "System Status" in mythfrontend.  I think
>> this is a big problem when you have a capture card whose inputs are all
>> temporarily unusable (e.g., disconnected).  You have to delete the
>> capture card and restart the backend if you don't want the scheduler to
>> try to use it to make recordings.
>> An easy way to address both above problems is to allow input connections
>> to be put in an "inactive" state.  Inactive in this context means that
>> they are not eligible for watching LiveTV or making recordings.  This
>> inactive state is what you would put the input connections in when
>> nothing is connected to them.  This can be implemented by adding a
>> boolean column to table cardinput with a default value of TRUE.  It
>> should not be allowed to assign active=TRUE and have no video source.
>> Currently, you can't even define an input connection without assigning a
>> video source to it.  Table cardinput does not get populated at all if
>> you don't assign a video source.  Similarly, rows are deleted from
>> cardinput if you delete the video source from them.  This means the
>> system throws away all the configuration data associated with the input
>> connection if you want to temporarily delete the association to the
>> video source.  This would no longer be necessary if the active/inactive
>> flag were there to tell you whether to use the input connection or not.
>> The reason the program guide doesn't show anything if you have no card
>> inputs with video sources is because the program guide needs to know
>> which channels have video sources.  But it shouldn't matter whether they
>> are currently usable (e.g. physically connected) to be able to look at
>> the listings.  If we no longer make input connections existence
>> dependent on their associated video sources, the system has all the data
>> it needs to be able to build the program guide and make schedules.
>> It seems like most of the code that would need to change would be
>> limited to code specifically involved in selecting input connections for
>> Live TV and making recordings.
>> I would be willing to implement and test this.
> I agree that a user should be able to define a capture card with no video
> sources on its inputs without the backend crashing.  I had this problem
> while I was trouble shooting my irblaster.  I didn't want MythTV to use 
> that
> capture card for recordings (yet) but I didn't want to have to redefine the
> card every time I wanted to work on getting the irblaster working.
> But I have to disagree with your idea that all defined channels should be
> shown in the listing even if they are not assigned to a card's input.  That
> sounds like a troubleshooting nightmare.  Plus why would I want to see a
> listing for something I can't watch/record?

I think it is a great idea. It will also mean that it is easy to define 
and have independent systems using myth for viewing, where there are no 
tuners attached. At present, I can't figure out how to do that on my 
laptop, although its suppose to be possible.

As to the channels being shown, I think it would be nice to be able to 
use, for example, this machine, to see what is 'on' tonight, even if I 
cannot record it *here*.

And even on the same machine, you may want to see a listing to check if 
a particular program is on when and where you think it is supposed to 
be, even if you cannot *at this instant* record it. You may be testing 
your antenna setup, and want to check if a program is on which uses your 
HD3000 card. In which case, you can set the antenna inactive and 
re-activate the QAM setup.

Great idea.

Can I help?


              R. Geoffrey Newbury			
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