[mythtv-users] External Channel Change Script for DVB cards

Mike Perkins mikep at randomtraveller.org.uk
Sun Oct 30 16:58:19 UTC 2011

On 30/10/11 12:25, Raymond Wagner wrote:
> On 10/30/2011 08:11, Colin Albert wrote:
>> On 10/29/2011 11:29 AM, Devin Heitmueller wrote:
>>> On Sat, Oct 29, 2011 at 10:39 AM, Colin Albert<colintrebla at gmail.com>   wrote:
>>>> I am reviving and old thread.  It relates to an issue that is a problem for
>>>> me and will be an ever increasing problem as Cable companies continue to
>>>> adopt SDV.
>>>> The problem: I have a QAM card and want to build a MythTV box instead of
>>>> using the cable company's (busted/worthless) DVR. The cable company uses
>>>> SDV, so QAM is limited to OTA locals.
>>>> My solution: get a set top box from the cable company, hook it to my
>>>> MythTV.  Use a External channel change script to change channels so that the
>>>> box is requesting the channel that I want. Then change the channel on the
>>>> QAM card to that channel.
>>> This won't work.  The RF output on the set top box is NTSC (analog
>>> only).  You won't be able to tune to it with a QAM tuner.  You would
>>> have to use an analog tuner set to channel 3.
>> But if I spit the input to the cable box then let the cable box and the
>> QAM card tune the same channel.  I am only using the cable box to
>> request the cable co to send that channel to my house.  Once it is being
>> broadcast I can receive it normally on the QAM card.
> You would have absolutely no idea where it is sending that channel to,
> so you would have no way to tune it with the QAM tuner.  Even if you did
> have a couple minutes to perform a channel scan, there would be no
> identifying information to denote it as such.  Even should someone write
> proper USB tuning adapter support for Linux, my bet is that the updated
> tuning data would come through an OOB event, rather than over the USB
> connection.
I'm confused here. You've just got an STB from the cableco so that you can tune 
the channel you want. Why not just use the composite/component outputs from the 
STB and feed them into a PVR-150/250 or HD-PVR? Why dick around trying to guess 
which channel the cableco is going to pick to send your program on?


Mike Perkins

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