[mythtv] Input switching question

Jerry Rubinow jerrymr at gmail.com
Fri Feb 17 06:48:55 UTC 2006

On 2/17/06, David Engel <gigem at comcast.net> wrote:
> On Thu, Feb 16, 2006 at 12:09:32PM -0500, Jerry Rubinow wrote:
> > The consequence would be that if someone was watching
> > live tv on a recorder in an input group, and the scheduler told
> > another recorder in that IG to start recording, the person watching
> > live would see the show change out from under them when the external
> > tuner got its channel changed.
> Consider the following example.  Using this feature, someone sets up
> their HDTV card to record both digital and analog TV.  Now, say they
> are watching live TV using the analog input and the scheduler kicks of
> a recording on the digital input.  The recording will fail because the
> device driver won't allow the digital input to be opened until the
> analog input is completely closed.

Tonight I've been studying a bunch of the main classes in myth, trying
to get a better sense of how things work together.  One thing I could
use a little help with - I didn't get to the point where I found the
structures that describe a card like the pchdtv-2/3000 that has both
analog and HD tuners on it.  I don't _think_ it's treated as two
separate cardids.  So while I understand your example, I'm not sure
how to think about how it might be solved yet.  I take it that
currently, this case is not handled in myth?

> > However, that situation can already happen in Myth as it is now, so no
> > one would be any worse off, but they'd have the added capabilities of
> > #1 and #2.  Or does implementing #1 and #2 compilcate or make worse
> > the symptoms of #3 somehow?
> As usual, the devil is in the details.  Until there is a complete plan
> for all 3 together, you can't say that any one is done.

True, and I agree that it would be good to have at least a roadmap for
#3 before starting 1 and 2.

> > Of course it would be best to have all three, and the only reason I'm
> > proposing postponing #3 is that I'm in need of Input Groups now and I
> > think I may be capable of implementing #1 and #2, but probably am not
> > qualified for #3 (and #3 isn't as important for my system
> > specifically).
> Don't sell yourself short.  If you're capable of dong 1 and 2, you
> should be capable of doing 3 too.

Well I'll give it the old college try anyway.  I spent an hour or two
looking at class structures and relations tonight - MainServer,
Scheduler, EncoderLink, TVRec, ProgramInfo, etc.  I still need to get
a better handle on how the different video cards and tuners within
them are represented.

> > Because of the nature of development, I can't assume
> > that anyone else is going to be working on this any time soon, but I
> > would like any changes I make to be integrated in to the dev tree.
> It's been on my TODO list for a while, but it's very low priority.  If
> you're willing to do the grunt work, I, and possbily Bruce too, would
> probably be willing to point you in the right direction and provide
> feedback.

That would be very helpful and appreciated.  It would make myth a lot
more useable for me if I could get this in there, and I've seen it
come up every so often on the user list, so I think it would be useful
to others as well.

Thanks for your comments.  Sleep now.


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