[mythtv] QAM tuning problem with HD-3000 & kernel DVB drivers

Taylor Jacob rtjacob at earthlink.net
Thu Jun 2 14:58:52 UTC 2005

Quoting Bruce Pennypacker <bruce at pennypacker.org>:
> I've been unable to tune QAM channels on my HD-3000 with mythtv despite
> being able to extract it using the azap, dtvscan, etc. tools.  In
> searching around I've come across many similar reports of problems with
> this combination.   I've tried both the 0.18.1 release and the CVS tree
> from yesterday with the same results - doing a channel scan simply
> results in all of the channels resulting in "Timeout Scanning Channel"
> when it's able to lock onto a channel.

If this has already been answered sorry but I am catching up on the -dev list
after a few days of ignoring it.. Are you using hte DVB drivers for starters? 
(I have to assume you are if you are scaning).. Can you tune to some
multiplexes where you know channels are and see if you can find an VCTs (i.e.
data on PID 0x1FFB).. Some cable systems don't send VCTs from what I have
gathered from the list and when the scaning app gets no meta data it just bails
out and gives up.. I need to change this, but I need to know if you are getting
VCTs very slowly, or if they are just not present at all..

> I was wondering if anybody knows about this problem and/or may be
> working on it.  It's been years since I've done any serious c/c++
> development/debugging and I know next to nothing about DTV, QAM, etc.
> but I was thinking of firing up gdb to see if I could figure out why
> this may be happening.  Of course I don't want to expend the effort if
> somebody else is already looking into it, hence my query here before I
> take the plunge.

I will be glad to assist you, but chances are I will be digging into this for
the next few days since my 5th gen Air2PC should be here tomorrow and I want to
make it work with Cable as well as 8VSB since thats what is specd out to do..


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