[mythtv-users] HDTV digital static with DVB

ffrr ffrr at tpg.com.au
Tue Nov 8 02:14:46 EST 2005


Preston Crow wrote:

>I'm having trouble with digital static-like artifacts on my HDTV
>recordings using the DVB drivers.  This seems to be unrelated to signal
>strength, but noticeably impacted by system load.  If I'm watching a
>recording or recording another channel on another tuner, the problem
>gets worse.
>
>I know that my system has the throughput to handle the bandwidth, so it
>seems that there's some buffer that's too small, but I haven't been able
>to find it.
>
>This has been an issue with my HD-2000 card for several months, so it's
>not a recent driver change.
>
>My system:
>HD-2000 with rooftop antenna for ATSC (works fine with video4linux drivers)
>Air2PC HD-5000 with digital cable QAM (works perfectly with non-HD channels)
>Kernel: 2.6.14 with CVS DVB drivers (for HD-5000 support).
>All DVB drivers built into the kernel (not modules).
>
>Probably irrelevant:
>ivtv-0.4.0 for PVR-250
>AMD 2500+
>SATA drive
>nVidia FX5200 with xvmc
>  
>
>

I chased video glitches from my DVB setup for ages, and with a lot of 
help from the list, I finally nailed it.  It was the Si 3112  SATA 
controller chip doing nasties on the PCI bus and corrupting the mpeg 
stream from the DVB card.

This would correlate with your observation that it is worse with system 
load, in particular disk access.



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