[mythtv-users] Why no External Channel Change Script for DVB cards?

[Mike Perkins]

Keith Wire wrote:
> Hi, I've been building my dream MythTV setup for several months and knocking
> off one issue at a time, but this one has me stumped.
> 
> My backend has a couple of pcHDTV HD-5500 cards and a Haupauge PVR-350.  I
> plan to use the HD-5500's to receive OTA HD, and connect the PVR-350 to my
> old DirecTV box.  I just put up a new antenna and Channel Master 9521A
> rotor.   This rotor has a remote and can be programmed to move to a
> predefined direction.  (I live in the boondocks of NW Ohio and am 60+ miles
> from any major TV towers, so I need to move the antenna to get a strong
> signal.)   I have created a script ( Antenna_GoToChannel.sh ) to run an IR
> Blaster to change the antenna to the proper preset position.  It works great
> from the command line.
> 
> Now I wanted to have MythTV call my script when I changed channels, but I
> see no "External channel change command" for the HD-5500 cards, only for the
> PVR-350.
> 
> I searched the Archives on Gossamer and someone said there was none for DVB
> cards, only V4L cards.
> 
> So I have two questions:
> 
> 1)      Is there really no place to call my script, or am I missing
> something?
> 
> 2)      If not, why?  Not complaining, I just want to understand.
> 
> Thanks, Keith
> 
You won't see any channel change scripts for DVB cards since, as they are 
plugged into the computer which is running the back end, Mythtv can change the 
channel directly. Providing, of course, it knows which card it is, and you 
specified that, anyway, in the setup procedure.

If Mythbackend sees an external channel change script in the settings, it will 
assume that you are using some kind of external box, and thus won't need to 
change the channel of the internal tuner. For example, with a PVR-350, you can 
plug the output of a set top box (or satellite tuner, etc) into the S-Video 
input. That's probably why you find references to PVR-350 and external channel 
change scripts.

As far as I know, you have an unusual setup. I suspect that the main response 
you will get here will be to install another aerial, and connect it to a second 
HD-5500 card.

However, it is possible that someone else may have another solution to your 
problem which won't involve buying more hardware.

-- 

Mike Perkins