[mythtv-users] Playback of HDTV, HDHomeRun

jedi jedi at mishnet.org
Thu Jul 17 14:51:31 UTC 2008


On Thu, Jul 17, 2008 at 01:33:14AM -0500, Dewey Smolka wrote:
> On Wed, Jul 16, 2008 at 11:36 PM, David Smiley <dsmiley at mac.com> wrote:
> >
> > I have a P4 at 2.8 GHz and I've been using it just fine with a Hauppage 250
> > card for nearly a year.
> 
> I'm in pretty much the same boat -- P4 2.5 with a Hauppage 250 and HDHR.

If the 250 is your display card then that might be your problem...

> 
> > I just purchased a flat screen TV and an HDHomerun.
> > I got the HDHomerun to record a snipped of a high-def program for just 11
> > minutes (which was 1.26 GB !).
> 
> This sounds about right. Maybe a bit on the high side but not far. I
> typically see around 6.5 to 9 GB per hour.
> 
> 
> > The playback is basically impossible; choppy
> > doesn't begin to describe it.  I suspect it's some sort of super high-res
> > MPEG2 format but I don't know how to get at info on my video files so I am
> > not certain.
> 
> I've got a similar problem (though not as bad as yours) that I've been
> trying to solve for some time now. Some channels (OTA) work very well,
> some are worse. Some channels are flawless, all are watchable, but
> some have minor problems with pixelization or stuttering.

    Have you checked the bitrates?

    I find that I see dramatically different bitrates between stations.

    I have had more troubles with the higher bitrate broadcasts.

    Although I have not had problems since tweaking my recording profiles.

> 
> There are a number of factors that could be involved. With these CPU
> specs, I would expect you need hardware acceleration via XvMC.
> 
> What's your video card? Are you using XvMC?
> 
> Beyond that, it could be:
> 
> A dirty signal -- have you tested your signal through, e.g. the HDHR's
> MS Windows utilities?

    MythTV is very picky about HD signal quality. This can crash your
backend or frontend or both.

> 
> Dirty cables -- are you sure you have good cables and aren't picking
> up any interference? What's the distance of coax between your
> antenna/source and HDHR? And powerful EM sources in between? Are you
> using a splitter to feed both inputs? Do you get a better result only
> feeding one input without a splitter?
> 
> Network congestion -- is your HDHR on a network node with any other
> devices? Is is going through a switch? How much other traffic is going
> on at the same time?

   I had problems with HD from my homerun and my AppleTV until I sorted
out some cpu related issues that were trashing my network performance.

[deletia]

> Your system should be HD capable with some adjustment, but it almost
> certainly requires XvMC and a bit of tweaking to the Playback
> Settings.
> 
> With a bit more info we can probably help sort you out.


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