[mythtv-users] Scheduling recordings from a satellite box

[Steve Daniels]

> -----Original Message-----
> From: mythtv-users-bounces at mythtv.org [mailto:mythtv-users-
> bounces at mythtv.org] On Behalf Of Kevin Kuphal
> Sent: 21 July 2006 02:15
> To: Discussion about mythtv
> Subject: Re: [mythtv-users] Scheduling recordings from a satellite box
> 
> JCA wrote:
> >> An additional comment: My satellite box and my PVR-150 are
> >> connected via an S-Video cable. After some googling I have got the
> >> impression that the channel 3 I mentioned does not apply in this case
> >> - which makes me wonder at what point in my mythtv configuration that
> >> assumption is being made? Help will be most appreciated; at this
> >> point, I am very confused.
> >>
> >> You still need to make the satellite box change channels so you get
> >> the right channel.
> >>
> >
> >    Thanks everybody for your feedback. There is, however, some
> > misunderstanding here, and I am sure that it is because I do not
> > understand things correctly and/or because I am not explaining clearly
> > what I mean. Let me try again.
> >
> >    Let's assume that I am interested to record shows from a single
> > channel, as received in my satellite box; say, channel 295. My
> > satellite box will always be tuned on channel 295. I know, this is not
> > realistic, but please bear with me. The point I want to make is that I
> > do not need to change the channel that the satellite box is tuned on
> > at the time that the recording is due to start.
> >
> >    OK, I now want to schedule a recording in mythtv. As I have
> > mentioned, using mythfrontend I select the Manage Recordings ->
> > Schedule -> Recordings -> Program
> > Guide menu. Here I can scroll down all the way to channel 295, and let
> > mythtv know that I want to record the show that starts at 3:00 PM,
> > lasting for one hour. Once this is done, I just exit from
> > mythfrontend.
> >
> >   At 3:00PM mythbackend tries to start the recording. But it can't,
> > because the only video signal it gets from the satellite box is on
> > channel 3. mythbackend just prints out the error messages I enclosed
> > earlier in this thread.
> >
> >   If, on the other hand, using the Program Guide menu from
> > mythfrontend, I specify that I want to record from channel 3, then
> > mythbackend is happy: When the time comes it indeed records the video
> > signal it is getting, which of course corresponds to channel 295 in
> > the satellite box, as mentioned three paragraphs above.
> >
> >   This is the issue that I want to sort out. I understand that the
> > situation I am describing is correct if the video signal is sent from
> > the satellite box to the PVR-150 board in my MythTV PC by means of a
> > coaxial cable. Is this still true if the signal is sent by means of an
> > S-Video cable instead?
> >
> You are confusing what channel the satellite box is *tuned* to, what
> frequency (channel) the satellite box *outputs* on the coax output, and
> what frequency (channel) the PVR-150 tuner is *tuned* to on the coax
> input.  The channel the satellite is tuned to matches the channels in
> your program guide.  These are important.  The frequency (channel) your
> satellite box outputs on coax must match the frequency (channel) the
> PVR-150 is tuned to but is unrelated to the program guide in any way.
> In your example you never want the PVR-150 to change the tuned channel
> so configuring a channel changing script is required.  Since you need
> something to match the program guide channel to the channel your
> satellite box tunes to, you require serial or IR control of your
> satellite box.  That being said...
> 
> Don't use the coax input/output.  It is only confusing you.  Use the
> s-video cable instead.  Now it should make more sense because there is
> no channel 3, just s-video input.  Myth then expects a channel changing
> script to handle the channel changes on the satellite receiver so it is
> tuned to the right channel.  Myth never tries to change channels on the
> PVR-150 tuner because you are not using, hence, no confusion.
> 
> Kevin

JCA,

In your example, your assuming that the Sat box is always tuned into the
right channel. Since Myth expects that it has to change the channel of
external devices, it uses an external channel change script. This script
either sends commands down a serial cable to you sat box, or to an IR
blaster which mimics your remote to tell the sat box to change channel.

What you are saying is that you will at the moment be changing the channels
on your sat box manually. But Myth still expects to be able to control the
external box. It expects channel change scripts to return a value of true so
it knows that it has successfully changed the channel on the external sat
box. You can trick myth into thinking it has a working channel change script
by setting the channel change script to be "/bin/true" without the quote
marks.

Hope this helps you understand,


Steve Daniels
 

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