[mythtv] Shouldn't MythTV disable the tuner between switching inputs?

Sam Logen starz909 at yahoo.com
Tue Jan 8 05:38:51 UTC 2008


--- David Backeberg <dbackeberg at gmail.com> wrote:

> So I don't know if this is still true, but it used
> to be that when you
> downloaded the ivtv sources (before mainline kernel
> adoption) the
> sources came with several contributed scripts. One
> of these was a
> command-line utility that accepted an argument and
> changed a tuner
> channel for you. MythTV accepts preferences to use
> an external command
> for changing a tuner channel. (This is how people
> with external tuners
> change channels on those tuners.) I actually used
> this utility with my
> PVR250 and Myth for a long time. If at a command
> line, outside of
> myth, you could say something like
> ./change_channel 33
> and then
> cat /dev/video0 > myfile.mpg
> or whatever, and you could use this to record from
> your card without a
> special program.

Hello David,

Yes, much of what you mention is true, there is a
utility from the ivtv developers called v4l2-ctl that
manages the driver and card, letting you change
channels and switch inputs.  I don't see, though, how
I can incorporate that program with mythtv.  From what
I can recall, it uses a separate command to switch
inputs, vs. changing frequencies.  Putting that
command in for Mythtv's default channel changer would
then only work for channel changing, not input
changing.


> Also, Myth itself would provide the
> argument to
> change to the requested channel if you wanted to do
> tuner changes with
> Myth and you set your preferences accordingly.
> 
> So my question: does that command line utility let
> you flip to the
> composite inputs? I don't have a PVR150 to find out.
> If so, voila,
> just add another channel and set the name to
> whatever argument the
> command-line utility wants. And if the utility
> doesn't let you do
> that, the source is there, and it shouldn't be too
> hard to change the
> code, right?

Hardly, I'm no programming whiz.

 And this won't break your regular
> channel changes.
> 
> I agree with other devs who think that Myth itself
> should be
> tuner-card agnostic and not have special code for a
> particular card.

I agree too, but if we're only talking about
transitioning from one input to another, that doesn't
use the card's tuner, then it's just one extra step to
disable the tuner, maybe save some power in the
process, who knows.

Kind regards,
Sam


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