[mythtv-users] Working around a lack of a IR Blaster
stefan_jones at comcast.net
stefan_jones at comcast.net
Sun Nov 22 22:55:04 UTC 2009
> From: "Nick Morrott" <knowledgejunkie at gmail.com>
> To: "Discussion about mythtv" <mythtv-users at mythtv.org>
> Sent: Sunday, November 22, 2009 10:30:27 AM GMT -08:00 US/Canada Pacific
> Subject: Re: [mythtv-users] Working around a lack of a IR Blaster
> 2009/11/22 <stefan_jones at comcast.net>:
> > I don't have a working IR Blaster but want to record a few select shows.
> > Shouldn't this work?
> > Set up Analog video tuner card.
> > Configure Input Connection to set tuner to a given channel (3).
> > Connect output of STB to tuner. Set the STB to the desired channel.
> > Put some dummy command in the outside tuner command line.
> Using /bin/true is the recommended way to 'fool' MythTV into thinking
> channel changing was successful in this scenario.
> > Record anything in the appropriate time slot to make the tuner record from
> > the STB for the appropriate length of time.
> > Now, I tried this out this afternoon. First I tried watching Live TV on the
> > Analog tuner. I saw the appropriate channel . . . the one that the STB was
> > tuned to.
> Expected if you have one or more tuners in the machine and (if more
> than 1 tuner) you configured the analog tuner's input connection
> _last_ in mythtv-setup. This gives the tuner the lowest recording
> priority (as long as you have not made any other tuner/channel/LiveTV
> priority changes) and will be used first for LiveTV.
> > Then I tried a test record. No dice. If I'm looking at the right messages,
> > another (digital) channel tried to tune in.
> This is again expected if the digital tuner(s) has a higher priority
> for _scheduled_ recordings. If you want to test the analog tuner for
> scheduled recordings, you need to tell the scheduler to prefer to use
> the analog tuner over other possibly higher-preference inputs. You can
> do this in the scheduling options for each recording rule where you
> want this to be the case.
> > Do I need to "scrub" the channels for the video source so they have no
> > tuning information? It seems to me that the Input Connection's channels just
> > need to supply a channel number . . . no tuning information that might cause
> > a digital tuner to try to take over.
> If you are using a video source that relies on using an external
> channel change script, you need to ensure that each channel configured
> on that input has a valid frequency value. In the case of controlling
> an STB, it is the digits you want passed to the changer script.
> A lack of tuning information will cause the recording to fail -
> another tuner will not try to take over.
Thanks, I think I've got things working.
* The error messages from the digital recorder in the mythfrontend console output were a red herring. I have two "ghost tuners" from a previous install. They don't show up in mythtvsetup, but their being in the DB causes errors on exit from mythtvsetup ("Tuner 8 is pointed at channel 71 which doesn't exist") and when mythfrontend starts up. I guess I'll have to use SQL to remove them.
* I changed priorities so that the analog tuner is 0, and the three digital tuners ranked 1,2 and 3.
* I removed all of the channels from the analog card's lineup that overlap with the digital card's range. (The digitals listen to the clear QAM stations on the cable signal . . . essentially the broadcast HD lineup plus SD digital versions of the low-tier cable TV channels; I added a "D" to the channel number to differentiate them. The analog tuner has its own lineup, consisting of the upper-tier cable channels that are now only viewable via the STB.)
* I wrote a little script called changechannel.sh to plug into the external tuner command line field. It writes the cable channel passed to it to a file. I'll eventually include the date as well. This will come in handy for debugging when the IR transmitter is functional.
* I was able to record two shows in a row. They look fine. The STB has a nice strong analog signal for the PVR-150 to pick up.
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