[mythtv-users] HD hardware: what next?

Greg Woods greg at gregandeva.net
Sun Jun 25 15:09:39 UTC 2006


After months of struggling, following directions from the Wiki and from
other pages I've been pointed to, trying everything I can think of, I am
forced to admit that HD recording is simply not going to work with the
hardware I have. I got HD display working after another long struggle
with Windows and PowerStrip, but it's not doing me any good without any
way to record HD. The system works great for anaolg/SD with a PVR-500,
but no HD recording. But the entire purpose of spending hundreds of
dollars and hours of labor on a new dedicated backend system was so that
I could do HD. If I just wanted SD/analog, my desktop as Myth server
worked great for that and I wouldn't have needed a dedicated MBE.
        
So now I need to change some hardware. I am risking throwing good money
after bad if there's something on this system that just is known not to
work, but if HD display works, the system can handle it. So on to the
questions:

FIREWIRE FROM MOTOROLA DCT-6412 CABLE BOX
        
Just flat out won't work. I have tried powering off the cable box,
unplugging the firewire cable, and rebooting the system countless times,
with various settings of broadcast vs. point-to-point, data rates, using
both test-mpeg2 and setting up the capture card within Myth, etc. and
all I get are empty files. plugreport shows that it is there, plugctl
can turn on and off the n_p2p_connections (although it has no apparent
effect on the bcast_connection parameter), but nothing. I know there are
channels available and that the connection is good, because the channel
changer in Myth works and because back in the beginning, I lucked into
having it work long enough to get a couple of HD snippets from it which
display fine. But I cannot get it to work. So the question: is there any
possibility that a PCI firewire card would work where the onboard
firewire ports of my ASUS P4P800-E motherboard won't? Or would that just
be a waste of money?

HD3000

It "sort of" works. I can load the DVB modules and access the card, I
have run the qamscan.sh script that uses dvb-apps tools to find channels
and there are 79 of them out there.  Most of those are digital music
channels or digital versions of SD/analog channels, but there are a
number of HD channels available. I can tune them with azap
(FE_HAS_LOCK), so I believe the card is set up correctly. I can also
tune them with the TV directly connected to the QAM cable, so I know the
channels are there and the signal is good. But I can't get a good
picture from the HD3000. It looks like it's all broken up and
hesitating, and the sound is garbled. I've been told that this is likely
some sort of signal interference but I don't know how to determine what
the source of the interference is or how to correct the problem. 
        
I tried moving the card to the very end PCI slot, as far from the CPU
and graphics card as possible. No help. I tried completely removing the
PVR-500 from the system in case there was interference from the other
tuners. No help. I'm out of options that don't require ripping the
machine completely apart, or purchasing new or different hardware.

Questions: first, is there any chance that the interference wouldn't
bother OTA signals? That would miss some channels I'd really like to
have (such as ESPN-HD and INHD), but it would be better than no HD at
all that I have now. I could try finding a way to wire an OTA antenna
down to the basement (putting the antenna down there where the system is
is guaranteed to fail, I have trouble even tuning standard FM radio down
there, so I'm looking at a major wiring project if I want to try this).
Or will the interference mess up the OTA signals the same as QAM?

Second, are there any other HD/QAM cards available that would be less
sensitive to the interference?

Third, is there any way to determine where the interference is really
coming from? I heard one person say that he fixed this problem by
replacing his power supply, but that's a financial and major labor
expense, not something I would want to do based on one piece of
anecdotal evidence.
        
Any advice at all gratefully accepted.

--Greg



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