[mythtv-users] Issues with using an IR blaster

[Cool Frood]

On 8/1/06, Michael T. Dean <mtdean at thirdcontact.com> wrote:
> On 08/01/2006 01:00 PM, Cool Frood wrote:
>
> >I've run against a couple of issues using the IR blaster with a
> >PVR-150 card. I'm running MythTV version 0.19.
> >
> >1.  The external channel changer command gets the frequency id instead
> >of the channel number when it is asked to change the channel.  I
> >looked into the sources and I could verify this and also rectify this.
> > Perhaps this is fixed in one of the bugfix releases.
> >
> >
>
> It definitely hasn't been fixed in any bugfixes (in 0.19-fixes or SVN
> trunk) because that's the desired behavior.  The freqid is the
> identifier used for a channel's frequency (which could be either a
> frequency in kHz /or/ a channel number); whereas, the channel number is
> the /user-specified/ number the user enters to tell Myth to change to
> another channel.  In other words, users can (and do) change channel
> numbers to anything they want instead of getting stuck with the cable
> companies idiotic^H^H^H^H^H^H^H"good-for-us-but-not-for-users" numbering
> scheme (i.e. putting Fox 35 on channel 3--users can, instead, change Fox
> 35 to be on channel 35).
>
> When using an external channel change script that requires channel
> number, you /must/ specify the channel number in the freqid field
> instead of a frequency in kHz.  (Note, also, that in the case I referred
> to above, that would mean channel 3--the channel number used by the
> external cable box--instead of channel 35.)  You may edit the values in
> the freqid field inside the mythtv-setup channel editor.
>

I get it now, thanks.  However, what threw me off was that as a user,
I didn't even know what the freqid was because it wasn't something
that I had to set up.  All the documentation says that the channel
changer script gets the channel number as its argument.  Perhaps it
would make sense to document this.  I'll put it up on the wiki.

> >2. There is a setting to tune the TV-capture tuner to a particular
> >channel (in my case, channel 3) when using an external channel
> >changer.  The problem is that channel 3 is not in my database of
> >channels
> >
>
> The video source should provide a list of all channels that are
> available through that video source.  If your cable box is set up to
> output an RF-modulated signal on channel 3 (or channel 4), you specify a
> value for:
>
> Preset tuner to channel
> Leave this blank unless you have an external tuner that is connected to
> the tuner input of your card. If so, you will need to specify the preset
> channel for the signal (normally 3 or 4).
>
> If you're having issues with this option, see
> http://www.gossamer-threads.com/lists/mythtv/users/209677#209677 and
> http://www.gossamer-threads.com/lists/mythtv/users/193785#193785
>
> > even though it is part of the data received from zap2it.  My
> >question is, how do I fix the channel data received from zap2it.
> >
> >
>
> Huh?  How can it be not be there, but be there?  What do you need to fix?
>
> >Secondly, why should MythTV go looking for channel 3 in the database
> >anyway if you have an external channel changer?
> >
>
> It won't unless you tell MythTV to change to channel 3--at which point,
> if it's not a valid channel, Myth tells you that it doesn't exist (how
> could Myth change to a channel that doesn't exist).
>
> Just in case this helps...  If you're using an RF-modulated output from
> your cable box on channel 3, you specify that in the "Preset tuner to
> channel" setting, then you tell Myth to change to the channel you want
> to watch (i.e. 217).  Myth then sets the capture card to channel 3 and
> sends the freqid (which should be 217) to the external channel change
> script.  The external channel change script then tells the
> cable/satellite box to change to channel 217.  And, it's quite possible
> that the video source may not have a channel 3--if the cable company
> doesn't use that channel number--which is fine because you're watching
> channel 217, not channel 3 (only the capture card is tuned to channel 3
> and only because you're using RF-modulated output on channel 3 from the
> cable/satellite box).
>
> (However, as mentioned above, the "Preset tuner to channel" setting may
> not work now, so you may want to add an appropriate line to your channel
> change script to change the capture card to the appropriate channel.)
>

I think I confused two issues because at that time, my channel
database was somehow not showing channel 3 so I assumed that the
reason I couldn't get the capture card to tune to a preset channel was
because of that.  In any case, I'll try the workaround and see how it
goes.  Also, I'm planning to use S-Video from the cable box to the
capture card, to the problem will go away anyway.

> Mike

-Akshat