[mythtv-users] Looking for HDTV Tuner Diagnostic Tips (AirStar-HD5000)

Joel Newcomb joelnewcomb at verizon.net
Sun May 20 15:45:31 UTC 2007

On Sat, 2007-05-19 at 21:06 -0400, William Munson wrote:

> Dale wrote:
> > Hi,
> >
> > I have an AirStar-HD5000AV-PCI card running on my backend MythTv system. It
> > records standard definition (SDTV) digital flawlessly. No pixelation at
> > all. However, when I record HDTV content I get many "bursts" of pixelated
> > areas on the playback. They occur roughly every 4 to 10 seconds and show as
> > horizontal defects that are several scanlines tall. 
> >
> > I'm pulling the QAM 256 modulated digital video from my TimeWarner system.
> > The card taps in right at the incoming cable. The digital STB from
> > TimeWarner works flawlessly and it's much farther down the cable than my
> > MythTv backend.
> >
> > My first thought is that perhaps the caching between the capture card and
> > hard drive is not working well. I'm just not sure how to set or diagnose
> > this. I've been a software developer (Assembly, C/C++ ...) for many years
> > but Linux is fairly new to me.
> >
> > My analog capture cards work capture excellent quality video. Much better
> > than my Tivo Series 1 in it's best quality mode.
> >
> > My system is comprised of:
> >
> > Athlon XP 3000+
> > 2 GB of RAM
> > Two PVR 150 analog capture cards (they usually not capturing while HDTV is)
> > One AirStar-HD5000AV-PCI card
> > 500 GB Maxstor 7H500 SATA drive.
> > NVIDIA GPU GeForce FX 5200
> >
> > Dale
> >   
> I don't have an answer to your question but wanted to chime in that I am 
> also getting many glitches from my ComCrap cable (20+ in any 1 hour show 
> with no discernible pattern or timing) and I was wondering if there was 
> a tool to measure the number/type of disruptions. I have a HDHR 
> connected via a dedicated high speed switch. I have a AthlonXP 3200+ 
> overclocked to 2.6GHz, 512M ram, 2 pvr250's and a FX5200 video card.
> It would really be helpful to me if I could prove that the glitches are 
> in the source stream and not in my setup.
> Bill
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Do not know if this helps, but I have noticed glitches in digital only
channels after I added an amplified splitter. My first digital box from
TW was working fine until I needed another TV connection. Not wanting to
degrade the signal I bought the amp with extra outputs. Did not put all
this together until I switched to Fios. Same story, they disconnected my
amplified splitter and install a passive with only 4 connections. A week
later I re-installed the amp to get the Mythbox on line again. Same
problems are present in fast paced digital movies. My next step is to
install another passive splitter to see if the problem disappears. There
were some posts regarding tuner card sensitivity to high inputs, maybe a
cheap attenuator is the answer. My other SD TVs do not have problems.
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