[mythtv-users] Playback of HDTV, HDHomeRun

[Dewey Smolka]

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.

> 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.

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?

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/O congestion -- What type/speed of HDD are you using? Are you trying
to play back while recording? Do you have your MySQL database on the
same drive as your recordings? Are there any other disk operations
(e.g. transcoding, com flagging, mythfilldatabase, etc) happening at
the same time?

> An auto-transcode of this file brought it down to only 1.1 GB
> but that didn't help the playback (unsurprisingly).

This would seem to suggest a capture issue rather than a playback
issue. But are you sure the artifacts or other distortions are exactly
the same on the original file and the transcoded file?

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.