[mythtv-users] DVICO Fusion HDTV 5 Lite vs HD3000

[Michael Haan]

On 1/17/06, Brandon Beattie <brandon+myth at linuxis.us> wrote:
>
> On Tue, Jan 17, 2006 at 03:20:59PM -0500, Michael Haan wrote:
> > > How often does it do this?  Is it always the same channel?  What is
> your
> > > receiving signal strength?
> > >
> > > --Brandon
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> > >
> >
> > Started off, this was happening in myth when watching hd recordings.  If
> a
> > recording froze, it would consistently freeze in the same place.  So I
> > manually record off of the 3000 using azap.  Playing back with mplayer
> > causes mplayer to dump at the same spot everytine.  It seems to happen
> on
> > most channels, eventually.
>
> By the design of HD tuners, you either get the data or not, there's no
> middle ground.  If you're getting corrupt data part way through it's
> either because you can't write to disk fast enough (Or your system is
> under a huge amount of stress) and myth's file
> writer thread discards the data, or, you're not receiving a good and
> steady signal.  If you're not getting good enough signal all the time then
> you can't expect a tuner card to work well.  Tree's moving is probably the
> most common cause of "it works good most of the time" situation.
> Sometimes a plane or helicopter can block the signal long enough that
> even the redundant data sent in an MPEG2-TS stream isn't enough and so
> you lose data.  If an app is choking on bad data it's the apps fault, or
> your fault for not giving it a steady enough signal.  There's no such
> instance as "The tuner is causing corrupted data" it just not possible.
> The hardware logic in the analog to digitial converter is the same or
> near identical in every HD tuner made, depending on chipsets.  It works,
> or doesn't work.  ... And if it's not working, fix the signal or what
> the processed data is being sent to.
>
> --Brandon
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>

I understand what you're saying.  The first thing I would note is that this
is QAM not satellite so trees etc aren't the issue.  The machine is an AMD64
3800+ writing to a raid 5 array.  Granted, the array is software raid, but
watching live HD, my cpu hangs around 10-20%, so I think it's fine.  So, I'm
trying to figure out what to look at next.  One final point:  watching HD
through the HD3000 I get occasional pixelation but if I then switch over and
watch the same channel through firewire, there is no pixelation.  Just seems
like that points the the card.
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